android - 如何检测 View 的高度？

Question

我有两种布局:

ma​​in.xml:

<?xml version="1.0" encoding="utf-8"?>
<ScrollView 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">

    <RelativeLayout
        android:id="@+id/addhere"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
    </RelativeLayout>

</ScrollView>

a.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:layout_height="200dp"
        android:layout_width="match_parent"/>

</LinearLayout>

我想膨胀 a.xml 布局并将其添加到 ID 为 addhere 的 View 组，然后检测 a 的 View 的高度。 a.getHeight() 给我 0。

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        View a = getLayoutInflater().inflate(R.layout.a,null);
        ViewGroup b = (ViewGroup)findViewById(R.id.addhere);
        b.addView(a);
        Log.d("states", a.getHeight() + ""); // show me 0

    }

请告诉我如何检测 a 的 View 高度？

Answer 1

a.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
    @Override
    public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
        Log.d("states", "a's height: " + v.getHeight());
        a.removeOnLayoutChangeListener(this);
    }
});