为GridView添加动画效果

最新推荐文章于 2017-08-17 19:56:12 发布

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本文介绍了如何为Android的GridView添加动画效果。首先，需要创建一个Adapter，然后在适配器中实现动画逻辑，以此来增强用户体验。

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首先要为Gridview创建一个Adapter:

代码如下：

package com.example.adapter;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;

import com.example.meidiastudy.R;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;

public class ImageAdapter extends BaseAdapter {

	private List<Integer> picRes =  new ArrayList<Integer>();
	private Context myContext=null;
	
	
	public ImageAdapter(Context myContext) {
		this.myContext = myContext;
		initPic();
	}

	@Override
	public int getCount() {
		// TODO Auto-generated method stub
		return picRes.size();
	}

	@Override
	public Object getItem(int position) {
		// TODO Auto-generated method stub
		return picRes.get(position);
	}

	@Override
	public long getItemId(int position) {
		// TODO Auto-generated method stub
		return picRes.get(position).intValue();
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		// TODO Auto-generated method stub
		ImageView img = new ImageView(myContext);
		img.setBackgroundColor(0xff000000);
		img.setImageResource(picRes.get(position));
		img.setScaleType(ScaleType.CENTER);
		img.setLayoutParams(new GridView.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT));
		img.setPadding(3, 3, 3, 3);		
		return img;
	}
	
	public void initPic(){//利用java的反射机制加载所有的图片
		Field[] fields = R.drawable.class.getDeclaredFields();
		for (int i = 0; i < fields.length; i++) {
			if (fields[i].getName().startsWith("test")) {
				try {
					picRes.add(fields[i].getInt(R.drawable.class));
				} catch (IllegalAccessException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (IllegalArgumentException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}

}

MainActivity:

package com.example.meidiastudy;

import com.example.adapter.ImageAdapter;

import android.os.Bundle;
import android.app.Activity;
import android.graphics.Matrix;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.view.animation.AnimationSet;
import android.view.animation.Interpolator;
import android.view.animation.RotateAnimation;
import android.view.animation.ScaleAnimation;
import android.view.animation.TranslateAnimation;
import android.widget.GridView;
import android.widget.ImageView;

public class MainActivity extends Activity {

	private GridView myGridView=null;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		myGridView = (GridView) findViewById(R.id.myGridView);
		myGridView.setAdapter(new ImageAdapter(this));

再就是layoutxml文件：

<LinearLayout 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"
    android:orientation="vertical"
     >        
        <GridView 
            android:id="@+id/myGridView"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:numColumns="3"
            android:stretchMode="columnWidth"
            android:layoutAnimation="@anim/layout_animation"></GridView>
       
</LinearLayout>

animation 动画set_animation.xml：

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <alpha 
        android:fromAlpha="1.0"
        android:toAlpha="0.0"
        android:duration="3000"/>
    <scale 
        android:fromXScale="1.0"
        android:toXScale="0.0"
        android:fromYScale="1.0"
        android:toYScale="0.0"
        android:pivotX="50%"
        android:pivotY="50%"
        android:startOffset="100"
        android:repeatCount="3"
        android:duration="3000"/>

</set>

layout_animation.xml

<pre name="code" class="java"><?xml version="1.0" encoding="utf-8"?>
<layoutAnimation xmlns:android="http://schemas.android.com/apk/res/android" 
    android:delay="0.5"
    android:animationOrder="random"
    android:animation="@anim/anima_set">
</layoutAnimation>