我的前面几个博文中已经介绍过了如何获取本地图片和Bitmap、软引用、弱引用的使用方法。在这两个博文当中针对一个完整的Demo示例给大家讲解获取本地图片的非常有效、也是安卓官方推荐的方法。
**源代码在博文最后可以下载**。
不知道怎么回事，近来csdn写博文上传图片错误，不能上传图片，所以给不了大家效果图。我就文字介绍好了。整个Demo只有一个Activity中完成，加载本地图片在GridView中进行显示，同时点击每个图片可以对图片进行选中的操作，每个item图片右上角会给出对号的提示，，表示选中图片。所以整个布局界面也很简单，所以就不给出xml的布局文件了。 先给出Activity的代码如下：
/** * 多图选择的界面 */{String RESULT_URIS = “result_uris”;String INTENT_CLAZZ = “clazz”;ArrayList<Uri> uriArray = TreeMap<Long, Uri> selectedTree = new TreeMap<Long, Uri>();//存放已选中的图片的id和uri数据/**这个是SelectedTreeMap 的代码，非常简单的一个序列化元素。用于存放已经选中的图片TreeMap<Long, Uri> selectedTree public class SelectedTreeMap implements Serializable {private TreeMap<Long, Uri> treeMap;public TreeMap<Long, Uri> getTreeMap() {return treeMap;}public void setTreeMap(TreeMap<Long, Uri> treeMap) {this.treeMap = treeMap;}}*/private SelectedTreeMap selectedTreeMap = new SelectedTreeMap();private ImageAdapter adapter;private GridView gridView;private View loadView;//进度条Viewprivate Button doneBtn;private TextView selectedNum;AlphaAnimation outAlphaAni;(Bundle savedInstanceState) {super.onCreate(savedInstanceState); //To change body of overridden methods use File | Settings | File Templates.setContentView(R.layout.sdcard);createView();init();}/*** 创建视图* 整个布局包含四个组件，很简单*/() {gridView = (GridView) findViewById(R.id.sdcard);loadView = findViewById(R.id.load_layout);doneBtn = (Button) findViewById(R.id.ok_btn);selectedNum = (TextView) findViewById(R.id.selected_num);}/*** 初始化* 其中的 getIntent().getExtras();为null，所以clazz=null。这里是为了方便复用该Activity。*/() {Bundle bundle = getIntent().getExtras();if (bundle != null) {clazz = (Class) bundle.get(INTENT_CLAZZ);}else { Log.i(GridImage.class.getSimpleName(), “bundle == null”); }imageWorker = new ImageWorker(this);//这个bitmap是GridView中每一个item默认时的图片Bitmap b = Bitmap.createBitmap(new int[]{0x00000000}, 1, 1, Bitmap.Config.ARGB_8888);imageWorker.setLoadBitmap(b);adapter = new ImageAdapter(imageWorker, this);gridView.setAdapter(adapter);loadData();initAnimation();onItemClick();onScroll();doneClick();}/*** GridView中每个item图片加载初始化动画-渐隐渐显的效果*/() {float fromAlpha = 0;float toAlpha = 1;int duration = 200;inAlphaAni = new AlphaAnimation(fromAlpha, toAlpha);inAlphaAni.setDuration(duration);inAlphaAni.setFillAfter(true);outAlphaAni = new AlphaAnimation(toAlpha, fromAlpha);outAlphaAni.setDuration(duration);outAlphaAni.setFillAfter(true);}/*** 加载数据*/() {cursorTask = new LoadLoacalPhotoCursorTask(this);//获取本地图片的异步线程类/*** 回调接口。当完成本地图片数据的获取之后，回调LoadLoacalPhotoCursorTask类中的OnLoadPhotoCursor接口* 的onLoadPhotoSursorResult方法，把数据传递到了这里。*/cursorTask.setOnLoadPhotoCursor(new LoadLoacalPhotoCursorTask.OnLoadPhotoCursor() {(ArrayList<Uri> uriArray, ArrayList<Long> origIdArray) {if (isNotNull(uriArray) & isNotNull(origIdArray)) {GridImage.this.uriArray = uriArray;GridImage.this.origIdArray = origIdArray;loadView.setVisibility(View.GONE);adapter.setOrigIdArray(origIdArray);adapter.notifyDataSetChanged();}}});cursorTask.execute();}/*** 点击每一项选择图片*/() {gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {(AdapterView<?> parent, View view, int position, long id) {CheckBox selectBtn = (CheckBox) view.findViewById(R.id.select_btn);boolean checked = !selectBtn.isChecked();selectBtn.setChecked(checked);//adapter中保存已经点击过的图片的选中情况adapter.putSelectMap(id, checked);Uri uri = uriArray.get(position);if (checked) {selectedTree.put(id, uri);} else {selectedTree.remove(id);}if (doneBtn.getVisibility() == View.GONE&& selectedTree.size() > 0) {doneBtn.startAnimation(inAlphaAni);doneBtn.setVisibility(View.VISIBLE);} else if (doneBtn.getVisibility() == View.VISIBLE&& selectedTree.size() == 0) {doneBtn.startAnimation(outAlphaAni);doneBtn.setVisibility(View.GONE);}CharSequence text = selectedTree.size() == 0 ? “” : “已选择 ” + selectedTree.size() + ” 张”;selectedNum.setText(text);}});}/*** 滚动的时候不加载图片-该功能通过imageWorker中锁机制实现的。*/() {gridView.setOnScrollListener(new AbsListView.OnScrollListener() {(AbsListView view, int scrollState) {//SCROLL_STATE_IDLE表示停止滚动。if (scrollState == AbsListView.OnScrollListener.SCROLL_STATE_IDLE) {imageWorker.setPauseWork(false);} else {imageWorker.setPauseWork(true);}}(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {}});}/*** 点击“完成”-完成事件，由于clazz==null 所以该方法并不实现什么功能。*/() {doneBtn.setOnClickListener(new View.OnClickListener() {(View v) {if (clazz != null) {selectedTreeMap.setTreeMap(selectedTree);Intent intent = new Intent(GridImage.this, clazz);Bundle bundle = new Bundle();bundle.putSerializable(RESULT_URIS, selectedTreeMap);intent.putExtras(bundle);startActivity(intent);}else {Log.i(GridImage.class.getSimpleName(), “clazz==null”);}}});}/*** 判断list不为空* @param list* @return*/(ArrayList list) {return list != null && list.size() > 0;}() {super.onDestroy();cursorTask.setExitTasksEarly(true);imageWorker.setExitTasksEarly(true);}}可以一个人，可以几个人，一起放松那劳累的心情或者劳累自己的身体，
