Android基本界面事件处理——英制转换器与BroadcastReceiver的使用

1.  MainActivity

package com.example.test_kaoshi2;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.*;

public class MainActivity extends Activity
{

EditText edit_in,edit_cm;
Button button_in,button_cm;

@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

edit_in = (EditText)findViewById(R.id.edit_in);
edit_cm = (EditText)findViewById(R.id.edit_cm);

button_in = (Button)findViewById(R.id.button_in);
button_cm = (Button)findViewById(R.id.button_cm);

Button.OnClickListener btnLintener = new Button.OnClickListener(){

@Override
public void onClick(View v)
{
// TODO 自动生成的方法存根
switch(v.getId())
{
case R.id.button_in:
Intent intent1 = new Intent("com.example.test_kaoshi2");
intent1.putExtra("message1", "你点击了英制！");
String in = edit_in.getText().toString();
if(!in.isEmpty())
{
double a = Double.parseDouble(in);
double b = a/2.54;
edit_cm.setText(String.valueOf(b));
}
else edit_cm.setText("0");
sendBroadcast(intent1);
return;
case R.id.button_cm:
Intent intent2 = new Intent("com.example.test_kaoshi2");
intent2.putExtra("message2", "你点击了公制！");
String cm = edit_cm.getText().toString();
if(!cm.isEmpty())
{
float a2 = Float.parseFloat(cm);
double b2 = a2*2.54;
edit_in.setText(String.valueOf(b2));
}
else
edit_in.setText("0");
sendBroadcast(intent2);
return;
}
}

};

button_in.setOnClickListener(btnLintener);
button_cm.setOnClickListener(btnLintener);
}

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item)
{
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings)
{
return true;
}
return super.onOptionsItemSelected(item);
}

}


2.  MyBroadcast类

package com.example.test_kaoshi2;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;

public class MyBroadcast extends BroadcastReceiver{

@Override
public void onReceive(Context context, Intent intent)
{
// TODO 自动生成的方法存根
String msg1 = intent.getStringExtra("message1");
String msg2 = intent.getStringExtra("message2");

Toast.makeText(context, msg1, Toast.LENGTH_SHORT).show();
Toast.makeText(context, msg2, Toast.LENGTH_SHORT).show();
}

}


3.  AndroidManifest.xml文件核心代码
在 </activity>后加

<receiver android:name=".MyBroadcast">
<intent-filter>
<action android:name="com.example.test_kaoshi2"></action>
</intent-filter>
</receiver>类名、动作保持一致。