android - 自定义 ViewGroup LayoutParams 在android中不起作用
问题描述
出色地
我只是在 android 中学习自定义视图组，所以我制作了一个简单的视图组。我命名它LearnLayout
我有自定义布局参数，称为LearnLayoutParams
问题
当我对孩子使用自定义属性时。这些属性没有被解析，LearnLayoutParams我得到默认值
代码
这是我的代码文件
学习布局.java
这是自定义视图组类文件
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Color;
import android.os.Build;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.RequiresApi;
import com.test.learnviewpagertransformations.MainActivity;
import com.test.learnviewpagertransformations.R;
public class LearnLayout extends ViewGroup {
private static final String TAG = MainActivity.TAG;
public LearnLayout(Context context) {
super(context);
}
public LearnLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public LearnLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int maxWidth = 0;
int maxHeight = 0;
for(int i=0; i<getChildCount(); i++){
View childView = getChildAt(i);
if(childView.getVisibility() != GONE){
measureChildWithMargins(childView, widthMeasureSpec, 0, heightMeasureSpec, 0);
final LearnLayoutParams lp = (LearnLayoutParams) childView.getLayoutParams();
int childWidth = lp.leftMargin + childView.getMeasuredWidth() + lp.rightMargin;
int childHeight = lp.topMargin + childView.getMeasuredHeight() + lp.bottomMargin;
maxWidth = Math.max(childWidth, maxWidth);
maxHeight = maxHeight + childHeight;
}
}
setMeasuredDimension(maxWidth, maxHeight);
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
int fromLeft = getPaddingLeft();
int fromTop = getPaddingTop();
int fromRight = right - left - getPaddingRight();
int fromBottom = bottom - top - getPaddingBottom();
for(int i=0; i<getChildCount(); i++){
View childView = getChildAt(i);
if (childView.getVisibility() != GONE) {
final LearnLayoutParams lp = (LearnLayoutParams) childView.getLayoutParams();
childView.layout(
fromLeft + lp.leftMargin,
fromTop + lp.topMargin,
fromRight - lp.rightMargin,
fromTop + lp.topMargin + lp.height
);
childView.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
Log.i(TAG, "onLayout: " + lp.backgroundColor);
}
});
childView.setBackgroundColor(getColor(lp.backgroundColor));
fromTop = fromTop + childView.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;
}
}
}
@Override
public LearnLayoutParams generateLayoutParams(AttributeSet attrs) {
return new LearnLayoutParams(getContext(), attrs);
}
@Override
protected LearnLayoutParams generateDefaultLayoutParams() {
return new LearnLayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
}
@Override
protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
return new LearnLayoutParams(p);
}
@Override
protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
return p instanceof LearnLayoutParams;
}
public static class LearnLayoutParams extends MarginLayoutParams {
public int backgroundColor = 0;
public LearnLayoutParams(Context c, AttributeSet attrs) {
super(c, attrs);
TypedArray a = c.obtainStyledAttributes(R.styleable.LearnLayoutLP);
backgroundColor = a.getInt(R.styleable.LearnLayoutLP_layout_background_color, backgroundColor);
Log.i(TAG, "LayoutParams: " + backgroundColor);
a.recycle();
}
public LearnLayoutParams(int width, int height) {
super(width, height);
}
public LearnLayoutParams(ViewGroup.LayoutParams source) {
super(source);
}
}
private int getColor(int backgroundColor){
switch (backgroundColor){
case 0:
return Color.RED;
case 1:
return Color.BLUE;
case 2:
return Color.GREEN;
default:
return Color.BLACK;
}
}
}
activity_learn_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.test.learnviewpagertransformations.views.LearnLayout
android:background="#99ff99"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<View
app:layout_background_color="red"
android:layout_margin="50dp"
android:layout_width="100dp"
android:layout_height="100dp" />
<LinearLayout
android:id="@+id/testView"
android:gravity="center"
app:layout_background_color="blue"
android:layout_margin="50dp"
android:layout_width="100dp"
android:layout_height="100dp">
<TextView
android:textStyle="bold"
android:textColor="#fff"
android:text="Test"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>
<View
app:layout_background_color="green"
android:layout_margin="50dp"
android:layout_width="100dp"
android:layout_height="100dp" />
</com.test.learnviewpagertransformations.views.LearnLayout>
<!--<com.test.learnviewpagertransformations.views.CustomLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<!– put first view to left. –>
<TextView
android:background="@drawable/filled_box"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_position="left"
android:layout_gravity="fill_vertical|center_horizontal"
android:text="l1"/>
<!– stack second view to left. –>
<TextView
android:background="@drawable/filled_box"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_position="left"
android:layout_gravity="fill_vertical|center_horizontal"
android:text="l2"/>
<!– also put a view on the right. –>
<TextView
android:background="@drawable/filled_box"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_position="right"
android:layout_gravity="fill_vertical|center_horizontal"
android:text="r1"/>
<!– by default views go in the middle; use fill vertical gravity –>
<TextView
android:background="@drawable/green"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="fill_vertical|center_horizontal"
android:text="fill-vert"/>
<!– by default views go in the middle; use fill horizontal gravity –>
<TextView
android:background="@drawable/green"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical|fill_horizontal"
android:text="fill-horiz"/>
<!– by default views go in the middle; use top-left gravity –>
<TextView
android:background="@drawable/blue"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="top|left"
android:text="top-left"/>
<!– by default views go in the middle; use center gravity –>
<TextView
android:background="@drawable/blue"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="center"/>
<!– by default views go in the middle; use bottom-right –>
<TextView
android:background="@drawable/blue"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|right"
android:text="bottom-right"/>
</com.test.learnviewpagertransformations.views.CustomLayout>-->
</LinearLayout>
属性.xml
我为 layoutparams 制作的自定义属性
<declare-styleable name="LearnLayoutLP">
<attr name="layout_background_color">
<enum name="red" value="0" />
<enum name="blue" value="1" />
<enum name="green" value="2" />
</attr>
</declare-styleable>
我怎么想
onLayout 和 onMeasure 中缺少一些东西，因此我没有获得自定义属性的正确值。如果您即使在那个地方检查我的自定义 layoutparams 类，我也没有得到我使用过的值，我在日志中得到的所有值都是默认值，即 0
要求
请分享你的想法
我很乐意欢迎任何修改和改进
_/\_
解决方案
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