自由手記

package maximyudin.BatteryLevel;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.widget.TextView;

public class BatteryLevel extends Activity {
        private TextView tvBatteryLevel;
        
        private BroadcastReceiver mBatteryInfoReceiver = new BroadcastReceiver() {
                @Override
                public void onReceive(Context context, Intent intent) {
                        String action = intent.getAction();
                        if (Intent.ACTION_BATTERY_CHANGED.equals(action)) {

                                int level = intent.getIntExtra("level", 0);
                                int scale = intent.getIntExtra("scale", 100);

                                tvBatteryLevel.setText("Battery level: "
                                                + String.valueOf(level * 100 / scale) + "%");
                        }
                }
        };
        
        @Override
        public void onResume() {
                super.onResume();

                registerReceiver(mBatteryInfoReceiver, new IntentFilter(
                                Intent.ACTION_BATTERY_CHANGED));
        }

        @Override
        public void onPause() {
                super.onPause();

                unregisterReceiver(mBatteryInfoReceiver);                
        }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        tvBatteryLevel = (TextView) findViewById(R.id.tvBatteryLevel);
    }
}

XML程式碼

<?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"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:id="@+id/tvBatteryLevel" android:text="Battery level:"/>
</LinearLayout>