我想在一个自定义的ViewGroup类中膨胀一个XML-Layout-File,我的问题是它只会产生一个空屏幕。在Activity类中执行相同的操作可以很好地工作。下面是我的简单XML-Layout-File:
shownumberlayout.xml:
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#FFFFFF"
android:id="@+id/layoutForNumber">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/tvNumber"
android:layout_centerHorizontal="true"
android:textColor="#000000"
android:text="Test"
android:layout_centerVertical="true"
android:textSize="30dip">
</TextView>
</RelativeLayout>
下面是工作版本,在Activity ShowNumber
中膨胀shownumberlayout.xml
ShowNumber.class
public class ShowNumber extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LayoutInflater inflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
ViewGroup vg = (ViewGroup) inflater.inflate(R.layout.shownumberlayout, null);
setContentView(vg);
}
}
这将显示白色背景,黑色文本“Test”居中。
现在,在自定义ViewGroup
-Class中膨胀xml的版本:
ViewGroup.class
public class ViewNumber extends ViewGroup {
private LayoutInflater inflater;
public ViewNumber(Context context) {
super(context);
// TODO Auto-generated constructor stub
initView(context);
}
public ViewNumber(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
initView(context);
}
public ViewNumber(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
initView(context);
}
private void initView(Context context){
inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
inflater.inflate(R.layout.shownumberlayout, null);
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
// TODO Auto-generated method stub
}
}
ShowNumber.class公共类ShowNumber扩展了Activity {首次创建活动时调用的/**。*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ViewGroup vg = new ViewNumber(this);
setContentView(vg);
}
}
我正在做这件事,基本上就像在this答案解释。这只会产生一个空的黑屏。我做错了什么?
更新1
@Konstantin我应用了您的更改,但仍然只是一个空白屏幕,我还做了一个日志输出来获取孩子的数量。它始终保持为1,即使我向XML-Layout-File中再添加一个Textview。在更改之前,它始终保持为0。
public class ViewNumber extends RelativeLayout {
...
private void initView(Context context){
//inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
//inflater.inflate(R.layout.shownumberlayout, null);
View.inflate(context, R.layout.shownumberlayout,this);
Log.v("ViewNumber", "Number of Child: " + this.getChildCount());//output is 1,before it remains 0
}
...
}
@Sankar这是从Konstantin更改后的日志:
12-16 09:24:23.606: DEBUG/AndroidRuntime(8951): >>>>>>>>>>>>>> AndroidRuntime START <<<<<<<<<<<<<<
12-16 09:24:23.606: DEBUG/AndroidRuntime(8951): CheckJNI is OFF
12-16 09:24:23.606: DEBUG/dalvikvm(8951): creating instr width table
12-16 09:24:23.656: DEBUG/AndroidRuntime(8951): --- registering native functions ---
12-16 09:24:23.916: DEBUG/AndroidRuntime(8951): Shutting down VM
12-16 09:24:23.916: DEBUG/dalvikvm(8951): Debugger has detached; object registry had 1 entries
12-16 09:24:23.916: INFO/AndroidRuntime(8951): NOTE: attach of thread 'Binder Thread #3' failed
12-16 09:24:24.076: DEBUG/AndroidRuntime(8960): >>>>>>>>>>>>>> AndroidRuntime START <<<<<<<<<<<<<<
12-16 09:24:24.076: DEBUG/AndroidRuntime(8960): CheckJNI is OFF
12-16 09:24:24.076: DEBUG/dalvikvm(8960): creating instr width table
12-16 09:24:24.126: DEBUG/AndroidRuntime(8960): --- registering native functions ---
12-16 09:24:24.376: INFO/ActivityManager(78): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=org.customview.harold/.ShowNumber }
12-16 09:24:24.426: DEBUG/AndroidRuntime(8960): Shutting down VM
12-16 09:24:24.426: DEBUG/jdwp(8960): Got wake-up signal, bailing out of select
12-16 09:24:24.426: DEBUG/dalvikvm(8960): Debugger has detached; object registry had 1 entries
12-16 09:24:24.456: INFO/AndroidRuntime(8960): NOTE: attach of thread 'Binder Thread #3' failed
12-16 09:24:24.456: VERBOSE/ViewNumber(8923): Number of Child: 1
12-16 09:24:24.496: VERBOSE/RenderScript_jni(164): surfaceDestroyed
12-16 09:24:24.526: INFO/ActivityManager(78): Displayed activity org.customview.harold/.ShowNumber: 104 ms (total 104 ms)
12-16 09:24:24.576: DEBUG/dalvikvm(158): GC_FOR_MALLOC freed 10631 objects / 526248 bytes in 52ms
12-16 09:24:34.606: DEBUG/dalvikvm(164): GC_EXPLICIT freed 1776 objects / 106960 bytes in 91ms
更新2
内容终于正确显示出来了。缺少的是覆盖RelativeLayout-Sublcass中的方法onLayout
(感谢Franco):
public class ViewNumber extends RelativeLayout {
...
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
// TODO Auto-generated method stub
for(int i = 0 ; i < getChildCount() ; i++){
getChildAt(i).layout(l, t, r, b);
}
}
...
}
注意:稍后您还应该覆盖方法onMeasurement()
,但当前内容也可以正确显示,而不会覆盖它。
现在,来自Franco的方法initView
的解决方案没有将TextView居中对齐,而是将其放在左上角。来自Konstantin的解决方案将其正确地放在视图的中心:
public class ViewNumber extends RelativeLayout {
...
private void initView(Context context){
View.inflate(context, R.layout.shownumberlayout,this);
}
...
}
https://stackoverflow.com/questions/4448779
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