Threads Handler Demo : Thread « Development « Android

1. Android
2. Development
3. Thread

Threads Handler Demo

    
/***
  Copyright (c) 2008-2009 CommonsWare, LLC
  
  Licensed under the Apache License, Version 2.0 (the "License"); you may
  not use this file except in compliance with the License. You may obtain
  a copy of the License at
    http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
*/

package com.commonsware.android.threads;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.widget.ProgressBar;
import java.util.concurrent.atomic.AtomicBoolean;

public class HandlerDemo extends Activity {
  ProgressBar bar;
  Handler handler=new Handler() {
    @Override
    public void handleMessage(Message msg) {
      bar.incrementProgressBy(5);
    }
  };
  AtomicBoolean isRunning=new AtomicBoolean(false);
  
  @Override
  public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    setContentView(R.layout.main);
    bar=(ProgressBar)findViewById(R.id.progress);
  }
  
  public void onStart() {
    super.onStart();
    bar.setProgress(0);
    
    Thread background=new Thread(new Runnable() {
      public void run() {
        try {
          for (int i=0;i<20 && isRunning.get();i++) {
            Thread.sleep(1000);
            handler.sendMessage(handler.obtainMessage());
          }
        }
        catch (Throwable t) {
          // just end the background thread
        }
      }
    });
    
    isRunning.set(true);
    background.start();
  }
  
  public void onStop() {
    super.onStop();
    isRunning.set(false);
  }
}


//res\layout\main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
  <ProgressBar android:id="@+id/progress"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" />
</LinearLayout>



Using AsyncTask
/***
  Copyright (c) 2008-2009 CommonsWare, LLC
  
  Licensed under the Apache License, Version 2.0 (the "License"); you may
  not use this file except in compliance with the License. You may obtain
  a copy of the License at
    http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
*/

package com.commonsware.android.async;

import android.app.ListActivity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.SystemClock;
import android.widget.ArrayAdapter;
import android.widget.Toast;
import java.util.ArrayList;

public class AsyncDemo extends ListActivity {
  private static String[] items={"lorem", "ipsum", "dolor",
                                  "sit", "amet", "consectetuer",
                                  "adipiscing", "elit", "morbi",
                                  "vel", "ligula", "vitae",
                                  "arcu", "aliquet", "mollis",
                                  "etiam", "vel", "erat",
                                  "placerat", "ante",
                                  "porttitor", "sodales",
                                  "pellentesque", "augue",
                                  "purus"};
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    setListAdapter(new ArrayAdapter<String>(this,
                        android.R.layout.simple_list_item_1,
                        new ArrayList()));
    
    new AddStringTask().execute();
  }
  
  class AddStringTask extends AsyncTask<Void, String, Void> {
    @Override
    protected Void doInBackground(Void... unused) {
      for (String item : items) {
        publishProgress(item);
        SystemClock.sleep(200);
      }
      
      return(null);
    }
    
    @Override
    protected void onProgressUpdate(String... item) {
      ((ArrayAdapter)getListAdapter()).add(item[0]);
    }
    
    @Override
    protected void onPostExecute(Void unused) {
      Toast
        .makeText(AsyncDemo.this, "Done!", Toast.LENGTH_SHORT)
        .show();
    }
  }
}



//res\layout\main.xml
<?xml version="1.0" encoding="utf-8"?>
<ListView
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@android:id/list"
  android:layout_width="fill_parent" 
  android:layout_height="fill_parent"
  android:drawSelectorOnTop="false"
/>

   
    
    
    
  

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