Android 让GridView的高度为Wrap_content根据内容自适应高度

package com.jayway.components;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.GridView;

public class MyGridView extends GridView {
    public MyGridView(Context context) {
        super(context);
    }

    public MyGridView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyGridView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int heightSpec;

        if (getLayoutParams().height == LayoutParams.WRAP_CONTENT) {
            // The great Android "hackatlon", the love, the magic.
            // The two leftmost bits in the height measure spec have
            // a special meaning, hence we can‘t use them to describe height.
            heightSpec = MeasureSpec.makeMeasureSpec(
                    Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
        }
        else {
            // Any other height should be respected as is.
            heightSpec = heightMeasureSpec;
        }

        super.onMeasure(widthMeasureSpec, heightSpec);
    }
}

activity_main.xml

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

<ScrollView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <!-- Header One -->
    <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:focusable="true"
            android:text="Header 1" />

        <!-- Custom grid view holding the ‘Group 1‘ items -->
        <com.jayway.components.MyGridView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:numColumns="3"
            android:stretchMode="columnWidth"
            android:id="@+id/grid_view_1" />

        <!-- Header 2 -->
        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Header 2" />

        <!-- Custom grid view holding the ‘Group 2‘ items -->
        <com.jayway.components.MyGridView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:numColumns="3"
            android:stretchMode="columnWidth"
            android:id="@+id/grid_view_2" />
    </LinearLayout>
</ScrollView>

MainActivity.java

package com.jayway.app;

import java.util.ArrayList;

import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.app.Activity;

import com.jayway.components.MyGridView;

public class MainActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ArrayList labels = new ArrayList();
        for (int i = 0; i < 24; i++) {
            labels.add("Item " + i);
        }

        ArrayAdapter adapter = new ArrayAdapter(
                this, android.R.layout.simple_list_item_1, labels);

        MyGridView grid1 = (MyGridView) findViewById(R.id.grid_view_1);
        grid1.setAdapter(adapter);

        MyGridView grid2 = (MyGridView) findViewById(R.id.grid_view_2);
        grid2.setAdapter(adapter);
    }
}