接近傳感器 (Proximity Sensor)

通過接近傳感器 (Proximity Sensor)可以檢測到 Android 手機靠近我的臉, 進而做一些動作, 例如禁用觸摸功能，或關閉屏幕.

public class AndroidProximitySensorActivity extends Activity {
  /** Called when the activity is first created. */
 
 SensorManager mySensorManager;
 Sensor myProximitySensor;
 
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  
  mySensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
  myProximitySensor = mySensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);
  
  if (myProximitySensor == null){
   //No Proximity Sensor!
   
  }else{
   mySensorManager.registerListener(proximitySensorEventListener, myProximitySensor,SensorManager.SENSOR_DELAY_NORMAL);
  }
 }
 
 SensorEventListener proximitySensorEventListener = new SensorEventListener(){
  
  @Override
  public void onAccuracyChanged(Sensor sensor, int accuracy) {
   // TODO Auto-generated method stub
   
  }
  
  @Override
  public void onSensorChanged(SensorEvent event) {
   // TODO Auto-generated method stub
   
   if(event.sensor.getType()==Sensor.TYPE_PROXIMITY){
    //do something
   }
  }
 };
}

顯示標題進度條, setProgressBarIndeterminateVisibility()

要在標題欄顯示進度條, 首先在 setContentView() 前調用 requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS) 函數要求FEATURE_INDETERMINATE_PROGRESS 功能. 再通過調用 setProgressBarIndeterminateVisibility(true/false) 函數顯示/隱藏標題進度條.

package com.AndroidProgressTitle;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.Button;

public class AndroidProgressTitleActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
        setContentView(R.layout.main);
        
        Button showProgress = (Button)findViewById(R.id.showprogress); 
        Button hideProgress = (Button)findViewById(R.id.hideprogress);
        
        showProgress.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    setProgressBarIndeterminateVisibility(true);
   }});
        
        hideProgress.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    setProgressBarIndeterminateVisibility(false);
   }});
    }
}

<?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:text="@string/hello"
    />
<Button  
    android:id="@+id/showprogress"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="顯示標題進度條"
    />
<Button  
    android:id="@+id/hideprogress"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="隱藏標題進度條"
    />
</LinearLayout>

通過 XML 在文本視圖 (TextView) 設定陰影效果 (shadow)

<?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:text="@string/hello"
    android:shadowColor="#FFFFFF"
    android:shadowRadius="5"
    android:shadowDx="10"
    android:shadowDy="10"
    />
</LinearLayout>

android:onClick - 定義 onClick 事件回調函數

我們可以在佈局文件(main.xml)中通過 android:onClick 屬性, 直接定義 onClick 事件的回調函數.

實例:

<?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:text="@string/hello"
    />
<Button  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="Click Me"
    android:onClick="onClick"
    />
</LinearLayout>

package com.AndroidOnClick;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

public class AndroidOnClickActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }
    
    public void onClick(View view){
     Toast.makeText(AndroidOnClickActivity.this, 
       "Button Clicked", Toast.LENGTH_LONG).show();
    }
}