ImageLoad(二)

效果图：

第一个按钮是上篇文章写的就在Activity中下载图片并展示，第二个则使用一个Dialog展示下载的一组图片

MainActivity代码：

public class MainActivity extends Activity {
private List<ImageBean> list = new ArrayList<ImageBean>();
    private MyGridViewAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
private ProgressDialog dialog;
//按钮事件
@SuppressLint("InflateParams")
public void click(View v){
switch (v.getId()) {
case R.id.main_dialog2:
LayoutInflater factory = LayoutInflater
.from(MainActivity.this);
// 得到自定义对话框
final View DialogView = factory.inflate(
R.layout.grid_view, null);
// 创建对话框
final AlertDialog dlg = new AlertDialog.Builder(
MainActivity.this)
.setView(DialogView).create();
dlg.show();
for (int i = 0; i < 5; i++) {
           ImageBean bean = new ImageBean();
           list.add(bean);
       }
adapter = new MyGridViewAdapter(MainActivity.this, list);
       GridView gridview = (GridView) DialogView.findViewById(R.id.gridView);
       Button btn = (Button) DialogView.findViewById(R.id.gridView_btn);
       btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
dlg.dismiss();
}
});
       gridview.setAdapter(adapter);
       adapter.notifyDataSetChanged();
       String[] str = {"https://www.baidu.com/img/baidu_logo.gif",
        "https://www.baidu.com/img/baidu_logo.gif",
    "https://www.baidu.com/img/baidu_logo.gif",
    "https://www.baidu.com/img/baidu_logo.gif",
    "https://www.baidu.com/img/baidu_logo.gif",
       };
       // 启动异步线程加载网络图片
       new ImageLoadTask(adapter,str).execute();
break;
}
}
}

activity_main.xml:

<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"
    tools:context="com.example.dialogimageload.MainActivity" 
    android:orientation="vertical"
    >
    <Button
        android:id="@+id/main_dialog1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="loading_dialog下载单张图片" 
        android:onClick="click"
        />
    <Button
        android:id="@+id/main_dialog2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="loading_dialog下载多张图片" 
        android:onClick="click"
        />
    <ImageView 
        android:id="@+id/main_iv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />
</LinearLayout>

grid_view.xml:

<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"
    tools:context="com.example.dialogimageload.MainActivity" 
    android:orientation="vertical"
    >
    <GridView
        android:id="@+id/gridView"
        android:layout_width="match_parent"
        android:layout_weight="1"
        android:numColumns="4"
        android:layout_height="0dp"
        android:text="@string/hello_world" 
        />
    <Button
        android:id="@+id/gridView_btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello_world"
        android:onClick="click"
        />
</LinearLayout>

ImageBean:

public class ImageBean{
private Bitmap bitmap;
    private boolean isNeedBar = true;
    public ImageBean() {
        super();
    }
    public boolean isNeedBar() {
        return isNeedBar;
    }
    public void setNeedBar(boolean isNeedBar) {
        this.isNeedBar = isNeedBar;
    }
    public Bitmap getBitmap() {
        return bitmap;
    }
    public void setBitmap(Bitmap bitmap) {
        this.bitmap = bitmap;
    }
}

MyGridViewAdapter:

public class MyGridViewAdapter extends BaseAdapter{
    private Context context;
    private List<ImageBean> list = new ArrayList<ImageBean>();
    public MyGridViewAdapter(Context context, List<ImageBean> list) {
        this.context = context;
        this.list = list;
    }
@Override
public int getCount() {
return list.size();
}
@Override
public Object getItem(int position) {
return list.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LinearLayout layout = new LinearLayout(context);
        ImageView imageView = new ImageView(context);
        layout.addView(imageView);
        ImageBean bean = list.get(position);
        if (bean.getBitmap() != null) {
            imageView.setImageBitmap(bean.getBitmap());
        }
        if (bean.isNeedBar()) {
            ProgressBar bar = new ProgressBar(context);
            layout.addView(bar);
        }
        return layout;
}
}

ImageLoadTask:

public class ImageLoadTask extends AsyncTask<Void, Void, Void> {
    private MyGridViewAdapter adapter;
    private String[] list;
    public ImageLoadTask(MyGridViewAdapter adapter,String[] list) {
        this.adapter = adapter;
        this.list = list;
    }
    @Override
    protected Void doInBackground(Void... params) {
        for (int i = 0; i < adapter.getCount(); i++) {
            ImageBean bean = (ImageBean) adapter.getItem(i);
            Bitmap bitmap = BitmapFactory
                    .decodeStream(getStream(list[i]));
            bean.setBitmap(bitmap);
            bean.setNeedBar(false);
            publishProgress(); // 通知去更新UI
        }
        return null;
    }
    public void onProgressUpdate(Void... voids) {
        if (isCancelled()) {
            return;
        }
        // 更新UI
        adapter.notifyDataSetChanged();
    }
    public InputStream getStream(String urlStr) {
        InputStream inStream = null;
        try {
            URL url = new URL(urlStr);
            URLConnection conn = url.openConnection();
            conn.setConnectTimeout(10 * 1000);
            inStream = conn.getInputStream();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return inStream;
    }
}