Android编程实现图片透明的方法

<?xmlversion="1.0"encoding="utf-8"?>

<LinearLayoutxmlns:Android="http://schemas.android.com/apk/res/android"

android:orientation="vertical"android:layout_width="fill_parent"

android:layout_height="fill_parent">

  <ImageViewandroid:id="@+id/imageView"android:layout_width="wrap_content"

  android:layout_height="wrap_content"

  android:layout_gravity="center_horizontal"

  android:src="@drawable/icon"/>

  <Buttonandroid:id="@+id/alpha_plus"

  android:layout_width="wrap_content"android:layout_height="wrap_content"

  android:text="透明度增加"android:layout_gravity="center_horizontal"

  />

  <Buttonandroid:id="@+id/alpha_minus"

  android:layout_width="wrap_content"android:layout_height="wrap_content"

  android:text="透明度减少"android:layout_gravity="center_horizontal"

  />

</LinearLayout>

importandroid.app.Activity;

importandroid.os.Bundle;

importandroid.os.Handler;

importandroid.view.View;

importandroid.widget.Button;

importandroid.widget.ImageView;

publicclassTOUMINGDUextendsActivity {

  privateImageView imageView=null;

  privateButton alpha_plus=null;//透明度增加

  privateButton alpha_minus=null;//透明度减少

  privateintalpha=255;//记录ImageView的透明度

  Boolean flag=true;

  @Override

    publicvoidonCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);

    imageView=(ImageView)findViewById(R.id.imageView);

    alpha_plus=(Button)findViewById(R.id.alpha_plus);

    alpha_minus=(Button)findViewById(R.id.alpha_minus);

    alpha_plus.setOnClickListener(listener);

    alpha_minus.setOnClickListener(listener);

  }

  privateView.OnClickListener listener =newView.OnClickListener(){

    publicvoidonClick(View v) {

      //加加

      if(v==alpha_plus){

        alpha+=10;

        if(alpha>255){

          alpha=255;

        }

        imageView.setAlpha(alpha);

      }

      //减减

      if(v==alpha_minus){

        alpha-=10;

        if(alpha<0){

          alpha=0;

        }

        imageView.setAlpha(alpha);

      }

    }

  };

}

<ImageView

  Android:id="@+id/start"

  android:layout_width="150.px"

  android:layout_height="80.px"

  android:src="@drawable/start"

  android:layout_x="120.0px"

  android:layout_y="250.0px"

/>

publicclasstwoextendsActivityimplementsOnClickListener{

privateImageView start =null;// 开始

protectedbooleanisBrewing =false;// 按钮置换

publicvoidonCreate(Bundle savedInstanceState) {

    //设置全屏

    super.onCreate(savedInstanceState);

    requestWindowFeature(Window.FEATURE_NO_TITLE);

    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,      WindowManager.LayoutParams.FLAG_FULLSCREEN);

    setContentView(R.layout.two);

    // 绑定

    start = (ImageView) findViewById(R.id.start);

  start.setOnClickListener(this);

}

//开始

publicvoidstartView(){

Bitmap bmp=BitmapFactory.decodeResource(getResources(), R.drawable.stop);//打开资源图片

    start.setImageBitmap(bmp);

    isBrewing =true;

}

//停止

publicvoidstopView(){

Bitmap bmp=BitmapFactory.decodeResource(getResources(), R.drawable.start);//打开资源图片

    start.setImageBitmap(bmp);

    isBrewing =false;

}

  @Override

  publicvoidonClick(View v) {

    if(v==start){

      if(isBrewing)

        stopView();

      else

        startView();

    }

  }

}

importAndroid.app.Activity;

importandroid.content.Intent;

importandroid.os.Bundle;

importandroid.os.Handler;

publicclassqidongextendsActivity{

  @Override

  publicvoidonCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);

    newHandler().postDelayed(newRunnable(){// 为了减少代码使用匿名Handler创建一个延时的调用

      publicvoidrun() {

        Intent i =newIntent(qidong.this, Quwenapk.class);//通过Intent打开最终真正的主界面Main这个Activity

        qidong.this.startActivity(i);//启动Main界面

        qidong.this.finish();//关闭自己这个开场屏

      }

    },5000);//5秒，够用了吧

  }

}

<?xmlversion="1.0"encoding="utf-8"?>

<RelativeLayoutxmlns:android="http://schemas.android.com/apk/res/android"

  android:layout_width="fill_parent"

  android:layout_height="wrap_content"

  android:background="@drawable/qt800x480"

  >

<TextView

  android:id="@+id/qidong"

  android:layout_width="wrap_content"

  android:layout_height="wrap_content"

  android:textSize="15dip"

  android:layout_centerHorizontal="true"

  android:text="程序加载中.."

  android:layout_marginTop="250.dip"

  android:layout_marginLeft="90.dip"

  />

</RelativeLayout>