Risposte:
Se guardi il discorso che ho tenuto al giorno della Devoxx University (disponibile su parleys.com ) imparerai come farlo da solo. Durante il talk ho scritto FlowLayoutun'implementazione dal vivo sul palco per mostrare quanto sia semplice scrivere layout personalizzati.
L'implementazione è ospitata qui .
Dovresti usare FlexboxLayoutcon flexWrap="wrap"attributo.
<com.google.android.flexbox.FlexboxLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:flexWrap="wrap">
<!-- contents go here -->
</com.google.android.flexbox.FlexboxLayout>
Per le istruzioni di compilazione, vedere il repository github.
Ulteriori informazioni su questo: https://android-developers.googleblog.com/2017/02/build-forrect-layouts-with.html
Non ho abbastanza reputazione per pubblicare un commento alla risposta di Romain Guy, ma è lì che dovrebbe essere questa risposta (ho creato un account solo per condividere la mia modifica).
Ad ogni modo, vedo altre persone che hanno scoperto che la sua fantastica soluzione FlowLayout ha alcuni problemi. Ho potuto trovarne uno io stesso e ho visto, come altri, che alcuni bambini erano tagliati. Guardando in dettaglio l'algoritmo sembra essere un errore molto semplice nel calcolo dell'altezza. Quando l'ultimo figlio è quello che viene inserito su una nuova riga, l'altezza non è stata calcolata correttamente. Ho ripulito un po 'il calcolo (c'era uno strano uso di "height" rispetto a currentHeight).
La seguente modifica risolve il problema di "l'ultimo figlio è troncato se su una nuova riga":
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
int widthLimit = MeasureSpec.getSize(widthMeasureSpec) - getPaddingRight();
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
boolean growHeight = widthMode != MeasureSpec.UNSPECIFIED;
int width = 0;
int currentWidth = getPaddingLeft();
int currentHeight = getPaddingTop();
int maxChildHeight = 0;
boolean breakLine = false;
boolean newLine = false;
int spacing = 0;
final int count = getChildCount();
for (int i = 0; i < count; i++)
{
View child = getChildAt(i);
measureChild(child, widthMeasureSpec, heightMeasureSpec);
LayoutParams lp = (LayoutParams) child.getLayoutParams();
spacing = mHorizontalSpacing;
if (lp.horizontalSpacing >= 0)
{
spacing = lp.horizontalSpacing;
}
if (growHeight && (breakLine || ((currentWidth + child.getMeasuredWidth()) > widthLimit)))
{
newLine = true;
currentHeight += maxChildHeight + mVerticalSpacing;
width = Math.max(width, currentWidth - spacing);
currentWidth = getPaddingLeft();
maxChildHeight = 0;
}
else
{
newLine = false;
}
maxChildHeight = Math.max(maxChildHeight, child.getMeasuredHeight());
lp.x = currentWidth;
lp.y = currentHeight;
currentWidth += child.getMeasuredWidth() + spacing;
breakLine = lp.breakLine;
}
if (newLine == false)
{
width = Math.max(width, currentWidth - spacing);
}
width += getPaddingRight();
int height = currentHeight + maxChildHeight + getPaddingBottom();
setMeasuredDimension(resolveSize(width, widthMeasureSpec),
resolveSize(height, heightMeasureSpec));
}
C'è una libreria di Google, chiamata "flexbox-layout" . Si dovrebbe controllare.
Per usarlo in RecyclerView, puoi usare qualcosa del genere:
val layoutManager = FlexboxLayoutManager(activity)
layoutManager.flexDirection = FlexDirection.ROW
layoutManager.flexWrap = FlexWrap.WRAP
layoutManager.justifyContent = JustifyContent.FLEX_START
layoutManager.alignItems = AlignItems.FLEX_START
recyclerView.layoutManager=layoutManager
Come una delle risposte precedenti, ho iniziato con la soluzione qui: http://hzqtc.github.io/2013/12/android-custom-layout-flowlayout.html
L'ho esteso per tenere conto delle diverse altezze dei bambini come sotto.
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
// Custom layout that wraps child views to a new line
public class FlowLayout extends ViewGroup {
private int marginHorizontal;
private int marginVertical;
public FlowLayout(Context context) {
super(context);
init();
}
public FlowLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public FlowLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
private void init() { // Specify the margins for the children
marginHorizontal = getResources().getDimensionPixelSize(R.dimen.activity_half_horizontal_margin);
marginVertical = getResources().getDimensionPixelSize(R.dimen.activity_half_vertical_margin);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int childLeft = getPaddingLeft();
int childTop = getPaddingTop();
int lowestBottom = 0;
int lineHeight = 0;
int myWidth = resolveSize(100, widthMeasureSpec);
int wantedHeight = 0;
for (int i = 0; i < getChildCount(); i++) {
final View child = getChildAt(i);
if (child.getVisibility() == View.GONE) {
continue;
}
child.measure(getChildMeasureSpec(widthMeasureSpec, 0, child.getLayoutParams().width),
getChildMeasureSpec(heightMeasureSpec, 0, child.getLayoutParams().height));
int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();
lineHeight = Math.max(childHeight, lineHeight);
if (childWidth + childLeft + getPaddingRight() > myWidth) { // Wrap this line
childLeft = getPaddingLeft();
childTop = marginVertical + lowestBottom; // Spaced below the previous lowest point
lineHeight = childHeight;
}
childLeft += childWidth + marginHorizontal;
if (childHeight + childTop > lowestBottom) { // New lowest point
lowestBottom = childHeight + childTop;
}
}
wantedHeight += childTop + lineHeight + getPaddingBottom();
setMeasuredDimension(myWidth, resolveSize(wantedHeight, heightMeasureSpec));
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
int childLeft = getPaddingLeft();
int childTop = getPaddingTop();
int lowestBottom = 0;
int myWidth = right - left;
for (int i = 0; i < getChildCount(); i++) {
final View child = getChildAt(i);
if (child.getVisibility() == View.GONE) {
continue;
}
int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();
if (childWidth + childLeft + getPaddingRight() > myWidth) { // Wrap this line
childLeft = getPaddingLeft();
childTop = marginVertical + lowestBottom; // Spaced below the previous lowest point
}
child.layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
childLeft += childWidth + marginHorizontal;
if (childHeight + childTop > lowestBottom) { // New lowest point
lowestBottom = childHeight + childTop;
}
}
}
}
L'ho usato come soluzione per il wrapping di TextEdits su più righe. Spero che sia d'aiuto!
Ecco la classe personalizzata in cui puoi ottenere il layout come segue con l'aggiunta di una vista dinamica (chiamata anche FlowLayout).
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
/*
Created By Dhavalkumar Solanki
* */
public class FlowLayout extends ViewGroup {
private int line_height_space;
public static class LayoutParams extends ViewGroup.LayoutParams {
public int horizontal_spacing;
public int vertical_spacing;
/**
* @param horizontal_spacing Pixels between items, horizontally
* @param vertical_spacing Pixels between items, vertically
*/
public LayoutParams(int horizontal_spacing, int vertical_spacing) {
super(0, 0);
this.horizontal_spacing = horizontal_spacing;
this.vertical_spacing = vertical_spacing;
}
}
public FlowLayout(Context context) {
super(context);
}
public FlowLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
assert (MeasureSpec.getMode(widthMeasureSpec) != MeasureSpec.UNSPECIFIED);
final int width = MeasureSpec.getSize(widthMeasureSpec) - getPaddingLeft() - getPaddingRight();
int height = MeasureSpec.getSize(heightMeasureSpec) - getPaddingTop() - getPaddingBottom();
final int count = getChildCount();
int line_height_space = 0;
int xpos = getPaddingLeft();
int ypos = getPaddingTop();
int childHeightMeasureSpec;
if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST) {
childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.AT_MOST);
} else {
childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
}
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() != GONE) {
final LayoutParams lp = (LayoutParams) child.getLayoutParams();
child.measure(MeasureSpec.makeMeasureSpec(width, MeasureSpec.AT_MOST), childHeightMeasureSpec);
final int childw = child.getMeasuredWidth();
line_height_space = Math.max(line_height_space, child.getMeasuredHeight() + lp.vertical_spacing);
if (xpos + childw > width) {
xpos = getPaddingLeft();
ypos += line_height_space;
}
xpos += childw + lp.horizontal_spacing;
}
}
this.line_height_space = line_height_space;
if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.UNSPECIFIED) {
height = ypos + line_height_space;
} else if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST) {
if (ypos + line_height_space < height) {
height = ypos + line_height_space;
}
}
setMeasuredDimension(width, height);
}
@Override
protected ViewGroup.LayoutParams generateDefaultLayoutParams() {
return new LayoutParams(1, 1); // default of 1px spacing
}
@Override
protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
if (p instanceof LayoutParams) {
return true;
}
return false;
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
final int count = getChildCount();
final int width = r - l;
int xpos = getPaddingLeft();
int ypos = getPaddingTop();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() != GONE) {
final int childw = child.getMeasuredWidth();
final int childh = child.getMeasuredHeight();
final LayoutParams lp = (LayoutParams) child.getLayoutParams();
if (xpos + childw > width) {
xpos = getPaddingLeft();
ypos += line_height_space;
}
child.layout(xpos, ypos, xpos + childw, ypos + childh);
xpos += childw + lp.horizontal_spacing;
}
}
}
}
Esempio :
text_view.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tool="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="5dp">
<TextView
android:id="@+id/tvText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="19sp"
android:background="@drawable/unselected_tag"
android:textColor="@color/colorPrimary"
tool:text="Temp" />
</RelativeLayout>
activity_flow_layou_demo.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:id="@+id/tvTitleBusiness"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Business Interest "
android:textColor="@color/colorPrimary"
android:textSize="25sp" />
<com.example.tristateandroid2.radardemo.FlowLayout
android:id="@+id/flowBusiness"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</com.example.tristateandroid2.radardemo.FlowLayout>
</LinearLayout>
<LinearLayout
android:layout_marginTop="@dimen/activity_horizontal_margin"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:id="@+id/tvTitlePrivate"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Private Interest "
android:textColor="@color/colorPrimary"
android:textSize="25sp" />
<com.example.tristateandroid2.radardemo.FlowLayout
android:id="@+id/flowPrivate"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</com.example.tristateandroid2.radardemo.FlowLayout>
</LinearLayout>
</LinearLayout>
</ScrollView>
</RelativeLayout>
FlowLayouDemo.java
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
import java.util.ArrayList;
public class FlowLayouDemo extends AppCompatActivity {
private TextView tvTitleBusiness;
private FlowLayout flowBusiness;
private TextView tvTitlePrivate;
private FlowLayout flowPrivate;
private ArrayList<TagModel> arrayList;
private void findViews() {
tvTitleBusiness = (TextView) findViewById(R.id.tvTitleBusiness);
flowBusiness = (FlowLayout) findViewById(R.id.flowBusiness);
tvTitlePrivate = (TextView) findViewById(R.id.tvTitlePrivate);
flowPrivate = (FlowLayout) findViewById(R.id.flowPrivate);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_flow_layou_demo);
findViews();
addLayouts();
}
private void addLayouts() {
if (arrayList == null) {
arrayList = new ArrayList<>();
}
flowBusiness.removeAllViews();
flowPrivate.removeAllViews();
for (int i = 0; i < 75; i++) {
final boolean[] selected = {false};
View view = this.getLayoutInflater().inflate(R.layout.text_view, null);
final TextView textView = (TextView) view.findViewById(R.id.tvText);
if (i % 5 == 0) {
arrayList.add(new TagModel(i, false, "Business VIEW : " + i));
textView.setText("Busi VIEW To IS : " + i);
} else {
arrayList.add(new TagModel(i, false, "TEXT IS : " + i));
textView.setText("Busi IS : " + i);
}
textView.setBackgroundResource(R.drawable.unselected_tag);
textView.setTextColor(Color.parseColor("#3F51B5"));
textView.setTag(i);
if(i<=50){
flowBusiness.addView(view);
}else {
textView.setText("Priv View : "+i);
flowPrivate.addView(view);
}
textView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (selected[0]) {
selected[0] = false;
textView.setBackgroundResource(R.drawable.unselected_tag);
textView.setTextColor(Color.parseColor("#3F51B5"));
} else {
selected[0] = true;
textView.setBackgroundResource(R.drawable.selected_tag);
textView.setTextColor(Color.parseColor("#FFFFFF"));
}
}
});
}
}
}
Una revisione a @MattNotEquals () FlowLayout che supporta MarginLayoutParams.
Questa è solo un'implementazione minimalista di MarginLayoutParms per supportare i margini sinistro, destro, superiore e inferiore.
import android.content.Context;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
/**
* Original version courtesy of MattNotEquals() at http://stackoverflow.com/a/34169798/4515489 - 4/13/17.
* 7/15/17 Revised to support MarginLayoutParams.
*/
public class FlowLayout extends ViewGroup {
// Custom layout that wraps child views to a new line.
public FlowLayout(Context context) {
super(context);
}
public FlowLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public FlowLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int childLeft = getPaddingLeft();
int childTop = getPaddingTop();
int lowestBottom = 0;
int lineHeight = 0;
int myWidth = resolveSize(100, widthMeasureSpec);
int wantedHeight = 0;
for (int i = 0; i < getChildCount(); i++) {
final View child = getChildAt(i);
if (child.getVisibility() == View.GONE) {
continue;
}
child.measure(getChildMeasureSpec(widthMeasureSpec, 0, child.getLayoutParams().width),
getChildMeasureSpec(heightMeasureSpec, 0, child.getLayoutParams().height));
int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();
lineHeight = Math.max(childHeight, lineHeight);
final LayoutParams lp = (LayoutParams) child.getLayoutParams();
childLeft += lp.leftMargin;
childTop += lp.topMargin;
if (childLeft + childWidth + lp.rightMargin + getPaddingRight() > myWidth) { // Wrap this line
childLeft = getPaddingLeft() + lp.leftMargin;
childTop = lowestBottom + lp.topMargin; // Spaced below the previous lowest point
lineHeight = childHeight;
}
childLeft += childWidth + lp.rightMargin;
if (childTop + childHeight + lp.bottomMargin > lowestBottom) { // New lowest point
lowestBottom = childTop + childHeight + lp.bottomMargin;
}
}
wantedHeight += lowestBottom + getPaddingBottom(); // childTop + lineHeight + getPaddingBottom();
setMeasuredDimension(myWidth, resolveSize(wantedHeight, heightMeasureSpec));
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
int childLeft = getPaddingLeft();
int childTop = getPaddingTop();
int lowestBottom = 0;
int myWidth = right - left;
for (int i = 0; i < getChildCount(); i++) {
final View child = getChildAt(i);
if (child.getVisibility() == View.GONE) {
continue;
}
int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();
final LayoutParams lp = (LayoutParams) child.getLayoutParams();
childLeft += lp.leftMargin;
childTop += lp.topMargin;
if (childLeft + childWidth + lp.rightMargin + getPaddingRight() > myWidth) { // Wrap this line
childLeft = getPaddingLeft() + lp.leftMargin;
childTop = lowestBottom + lp.topMargin; // Spaced below the previous lowest point
}
child.layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
childLeft += childWidth + lp.rightMargin;
if (childTop + childHeight + lp.bottomMargin > lowestBottom) { // New lowest point
lowestBottom = childTop + childHeight + lp.bottomMargin;
}
}
}
@Override
public boolean shouldDelayChildPressedState() {
return false;
}
@Override
protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
return p instanceof LayoutParams;
}
@Override
protected LayoutParams generateDefaultLayoutParams() {
return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
}
@Override
public LayoutParams generateLayoutParams(AttributeSet attrs) {
return new FlowLayout.LayoutParams(getContext(), attrs);
}
@Override
protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) {
if (lp instanceof LayoutParams) {
return new LayoutParams((LayoutParams) lp);
}
else if (lp instanceof MarginLayoutParams) {
return new LayoutParams((MarginLayoutParams) lp);
}
else
return super.generateLayoutParams(lp);
}
/**
* Per-child layout information for layouts that support margins.
*/
public static class LayoutParams extends MarginLayoutParams {
public LayoutParams(@NonNull Context c, @Nullable AttributeSet attrs) {
super(c, attrs);
}
public LayoutParams(int width, int height) {
super(width, height);
}
public LayoutParams(@NonNull ViewGroup.LayoutParams source) {
super(source);
}
public LayoutParams(@NonNull ViewGroup.MarginLayoutParams source) {
super(source);
}
public LayoutParams(@NonNull LayoutParams source) {
super(source);
}
}
}
android:layout_margin="10dp"nel file di layout, o impostare i margini individuali con attributi quali android:layout_marginLeft="10dp", android:layout_marginTop="4dp", .etc.
Bel codice FlowLayout autonomo semplice qui (solo alcuni file gist.github concisi) :
http://hzqtc.github.io/2013/12/android-custom-layout-flowlayout.html
Tuttavia, l'attività lì fuori dagli schemi non ha funzionato per me per caricare il layout personalizzato.
Ho trovato questa soluzione [usando la chiamata a 2 parametri .inflate () da questo esempio ] :
@Override
protected void onCreate(Bundle savedInstanceState)
{
// ..
setContentView(R.layout.main_res_layout_activity_main);
ViewGroup flowContainer = getFlowLayoutView();
// ..
}
ViewGroup getFlowLayoutView()
{
LayoutInflater inflater = getLayoutInflater();
ViewGroup flowLayout =
(ViewGroup)
inflater.inflate(
R.layout.main_res_layout_activity_main,
(FlowLayout) findViewById(R.id.flow_container)
);
return flowLayout;
}
Ora è disponibile il supporto integrato in ConstraintLayout utilizzando un widget Flow. Ha molte opzioni che possono essere utilizzate per ottenere molti tipi di flussi.
Esempio:
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.constraintlayout.helper.widget.Flow
android:layout_width="0dp"
android:layout_height="wrap_content"
app:constraint_referenced_ids="item_1,item_2,item_3"
app:flow_horizontalBias="0"
app:flow_horizontalGap="10dp"
app:flow_horizontalStyle="packed"
app:flow_verticalGap="8dp"
app:flow_wrapMode="aligned"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<View
android:id="@+id/item_1"
android:layout_width="50dp"
android:layout_height="50dp" />
<View
android:id="@+id/item_2"
android:layout_width="50dp"
android:layout_height="50dp" />
<View
android:id="@+id/item_3"
android:layout_width="50dp"
android:layout_height="50dp" />
</androidx.constraintlayout.widget.ConstraintLayout>
Dai un'occhiata a questo post: https://medium.com/@tapanrgohil/constraintlayout-flow-bye-bye-to-linerlayout-78fd7fa9b679
E qui: https://www.bignerdranch.com/blog/constraintlayout-flow-simple-grid-building-without-nested-layouts/