Android开发之GridView的Item放大缩小

为了弄GridView中Item的放大缩小，弄了好久，纠结了好久，也找了好多资料，终于弄出来了。

一、效果图如下：

二、GridView实现九宫格比较容易，难的是实现动画放大和放大后不会被后面的Item覆盖的问题，有人说用View.Bringtofornt()可以解决，不过我试了好久都不行，可能我的方法不对，有高手使用View.Bringtofornt()实现成功的可以交流一下。我用的是另一种方法：继承GridView，实现protected int getChildDrawingOrder(int childCount, int i)方法。代码如下：MyGridView.java

package com.src;import android.annotation.SuppressLint;import android.content.Context;import android.util.AttributeSet;import android.widget.GridView;public class MyGridView extends GridView {private int position = 0;public MyGridView(Context context) {super(context);}public MyGridView(Context context, AttributeSet attrs) {super(context, attrs);setChildrenDrawingOrderEnabled(true);}public void setCurrentPosition(int pos) {// 刷新adapter前，在activity中调用这句传入当前选中的item在屏幕中的次序this.position = pos;}@SuppressLint("NewApi")@Overrideprotected void setChildrenDrawingOrderEnabled(boolean enabled) {// TODO Auto-generated method stubsuper.setChildrenDrawingOrderEnabled(enabled);}@Overrideprotected int getChildDrawingOrder(int childCount, int i) {if (i == childCount - 1) {// 这是最后一个需要刷新的itemreturn position;}if (i == position) {// 这是原本要在最后一个刷新的itemreturn childCount - 1;}return i;// 正常次序的item}}

三、然后在XML中使用重写的GridView定义控件：main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:gravity="center_horizontal"    android:orientation="vertical" >    <LinearLayout        android:layout_width="600dip"        android:layout_height="wrap_content"        android:orientation="vertical" >        <com.src.MyGridView            android:id="@+id/gridview"            android:layout_width="match_parent"            android:layout_height="match_parent"            android:background="#ffffff"            android:focusable="true"            android:gravity="center"            android:horizontalSpacing="1.0dip"            android:listSelector="@android:color/transparent"            android:numColumns="5"            android:stretchMode="spacingWidthUniform"            android:unselectedAlpha="0.2"            android:verticalSpacing="1.0dip" />    </LinearLayout></LinearLayout>

四、然后重写适配器继承BaseAdapter：ImageAdapter.java

package com.src;import java.util.ArrayList;import java.util.HashMap;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.GridView;import android.widget.ImageView;import android.widget.TextView;public class ImageAdapter extends BaseAdapter {private ArrayList<HashMap<String, String>> list = null;private int isSelect = -1;private int isClick = -1;private Context context;public ImageAdapter(Context context, ArrayList<HashMap<String, String>> list) {this.list = list;this.context = context;}public int getCount() {// TODO Auto-generated method stubreturn list.size();}public Object getItem(int position) {// TODO Auto-generated method stubreturn list.get(position);}public long getItemId(int position) {// TODO Auto-generated method stubreturn position;}public void setNotifyDataChange(int id) {isSelect = id;super.notifyDataSetChanged();}public void setNotifyItemSelected(int id) {isClick = id;super.notifyDataSetChanged();}public View getView(int position, View convertView, ViewGroup parent) {// TODO Auto-generated method stubViewHolder holder = new ViewHolder();if (convertView == null) {convertView = LayoutInflater.from(context).inflate(R.layout.gridview_item, null);holder.mImageView = (ImageView) convertView.findViewById(R.id.img);holder.mTextView = (TextView) convertView.findViewById(R.id.text);convertView.setTag(holder);} else {holder = (ViewHolder) convertView.getTag();}holder.mImageView.setImageResource(R.drawable.icon);String name = list.get(position).get("name");holder.mTextView.setText(name);convertView.setLayoutParams(new GridView.LayoutParams(150, 210));if (isClick == position) {holder.mImageView.setBackgroundResource(R.drawable.gvitemselect2);} else {if (isSelect == position) {holder.mImageView.setBackgroundResource(R.drawable.gvitemselect1);} else {holder.mImageView.setBackgroundResource(R.drawable.gvitemselect);}}return convertView;}class ViewHolder {public ImageView mImageView = null;public TextView mTextView = null;}}

五、在Activity中监听GridView事件实现放大缩小：GrideActivity.java

package com.src;import java.util.ArrayList;import java.util.HashMap;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.animation.Animation;import android.view.animation.AnimationSet;import android.view.animation.ScaleAnimation;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.AdapterView.OnItemSelectedListener;public class GrideActivity extends Activity implements OnItemClickListener,OnItemSelectedListener {private ArrayList<HashMap<String, String>> itemList = null;private ImageAdapter adapterItem = null;private MyGridView gridview = null;private AnimationSet manimationSet;ScaleAnimation scaleAnimation = new ScaleAnimation(1.7f, 0.8f, 1.7f, 0.8f,Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);ScaleAnimation scaleAnimation1 = new ScaleAnimation(1, 1.7f, 1, 1.7f,Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.main);itemList = new ArrayList<HashMap<String, String>>();for (int i = 0; i < 10; i++) {HashMap<String, String> map = new HashMap<String, String>();map.put("name", i + " item");itemList.add(map);}adapterItem = new ImageAdapter(this, itemList);gridview = (MyGridView) findViewById(R.id.gridview);gridview.setAdapter(adapterItem);gridview.setOnItemClickListener(this);gridview.setOnItemSelectedListener(this);gridview.smoothScrollToPosition(2);}/** * 播放动画 *  * @param view */private void startAnimation(View view) {AnimationSet animationSet = new AnimationSet(true);if (manimationSet != null && manimationSet != animationSet) {scaleAnimation.setDuration(500);manimationSet.addAnimation(scaleAnimation);manimationSet.setFillAfter(false);view.startAnimation(manimationSet);}scaleAnimation1.setDuration(500);animationSet.addAnimation(scaleAnimation1);animationSet.setFillAfter(true);view.startAnimation(animationSet);manimationSet = animationSet;}/** * 点击选中 */public void onItemClick(AdapterView<?> parent, View view, int position,long id) {// TODO Auto-generated method stubstartAnimation(view);gridview.setCurrentPosition(position);adapterItem.setNotifyItemSelected(position);}/** * 移动焦点 */public void onItemSelected(AdapterView<?> parent, View view, int position,long id) {// TODO Auto-generated method stubstartAnimation(view);gridview.setCurrentPosition(position);adapterItem.setNotifyDataChange(position);}public void onNothingSelected(AdapterView<?> parent) {// TODO Auto-generated method stub}}

项目源代码下载：http://download.csdn.net/detail/gaosunqiong/7937217