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嗨,我根据我的图像视图获取坐标值。所以,现在我试图在全局使用这些坐标值,但是我的方法返回了零(默认/初始值),但是它在方法内部打印了正确的值。请帮我..在android中返回默认值/初始值的方法
代码: MainActivity.java
public class StackActivity extends ActionBarActivity {
ImageView firstDot, middleDot, lastDot;
int distaceHoriz;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_stack);
firstDot = (ImageView) findViewById(R.id.img_dot_starting);
middleDot = (ImageView) findViewById(R.id.img_dot_middle);
lastDot = (ImageView) findViewById(R.id.img_dot_last);
distance(firstDot);
Log.e("distaceHorizFirst", distaceHoriz+"");
distance(middleDot);
Log.e("distaceHorizMiddle", distaceHoriz+"");
distance(lastDot);
Log.e("distaceHorizLast", distaceHoriz+"");
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.stack, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public int distance(final View view) {
view.getViewTreeObserver().addOnGlobalLayoutListener(
new OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
view.getViewTreeObserver()
.removeGlobalOnLayoutListener(this);
int[] locations = new int[2];
view.getLocationOnScreen(locations);
distaceHoriz = locations[0];
// int vertDistanceToLastDot = locations[1];
Log.e("distaceHoriz:", ""+ distaceHoriz);
}
});
return distaceHoriz;
}
}
MainLayout.xml
<ImageView
android:id="@+id/img_dot_starting"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_marginTop="42dp"
android:layout_alignParentLeft="true"
android:src="@drawable/icon_round" />
<ImageView
android:id="@+id/img_dot_middle"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_marginTop="42dp"
android:layout_centerHorizontal="true"
android:src="@drawable/icon_round" />
<ImageView
android:id="@+id/img_dot_last"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_marginTop="42dp"
android:layout_alignParentRight="true"
android:src="@drawable/icon_round" />
嗯,这是因为“OnGlobalLayoutListener”的异步特性。 'onGlobalLayout()'的内容不会立即执行,而是在不久的将来某个时候执行。然而,您的'distance()'方法同步运行,并立即返回一个默认值(因为实际赋值的代码尚未执行)。我认为你错误地认为通过让听众进入你自己的方法,它的回调就会立即执行。事实并非如此。 –