/** handler update data flag */
protected static final int MSG_UPDATE_DATA = 2;
protected static final int MSG_INSERT_DB = 0;
public void downloadData() {
updateUIThread( MSG_UPDATE_DATA );
mListView.refreshSelf();
}
public void updateUIThread( final int type ) {
new Thread( new Runnable() {
@Override
public void run() {
mUIhandler.sendEmptyMessage( type );
}
} ).start();
}
/** refresh UI handler */
private Handler mUIhandler = new Handler() {
public void handleMessage( android.os.Message msg ) {
switch ( msg.what ) {
case MSG_UPDATE_DATA:
updateListView( ( List<TaskReceiveRspJson> ) TaskDbManager .getData( TaskDbManager.TABLE_TASK_RECEIVE, mQueryByState ) );
break;
default:
break;
}
};
};
handler processing method
Message processing code:
private Handler handler = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case 1 :
bt.setText("Downloading...");
break;
case 2 :
Bitmap bm = (Bitmap) msg.obj;
iv.setImageBitmap (bm);
break;
case 3 :
Bundle bundle = msg.getData();
String data = bundle.getString("text");
bt.setText(data);
break;
}
}
};
Message sending code:
method one:
Example 1:
Message.obtain(handler,1).sendToTarget();
Example 2:
Bitmap bm = NetUtil.downloadNewImg();
Message.obtain(handler, 2, bm).sendToTarget();
Example 3:
// This message does not carry data, but a piece of code. When the main thread processes this message, it will execute the code it carries without executing other codes.
Message.obtain(handler, new Runnable() {
public void run() {
bt.setText("Download connotation map");
}
}).sendToTarget();
Method two:
Example 1:
handler.obtainMessage(1).sendToTarget();
Example 2:
Bitmap bm = NetUtil.downloadNewImg();
handler.obtainMessage(2, bm).sendToTarget();
Method three:
Example 1:
Message msg = new Message();
msg.what =1;
handler.sendMessage(msg);
Example 2:
Message msg = new Message();
msg.what =2;
msg.obj = bm;
handler.sendMessage(msg);
Example 3:
Message msg = new Message();
Bundle data = new Bundle();
data.putString("text", "Downloading...");
msg.what = 3;
msg.setData(data);
handler.sendMessage(msg);
Example 4:
// Create a message object with code and send it to the main thread for execution
handler.post(new Runnable() {
public void run() {
// In the main thread, execute when processing messages
Toast.makeText(
MainActivity.this, "Download finished",
Toast.LENGTH_SHORT).show();
}
});
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