009.切換圖片：setImageResource

• 布局：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="${relativePackage}.${activityClass}" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="onClick"
        android:text="Button" />

</LinearLayout>

• MainAvtivity.java

package com.example.app9;

import android.app.Activity;
import android.content.res.Resources;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class MainActivity extends Activity {

    ImageView imageView;
    Button btn1;
    int n = 0;

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

        imageView = (ImageView) this.findViewById(R.id.imageView1);
        btn1 = (Button) this.findViewById(R.id.button1);

    }

    public void onClick(View view) {
        Resources res = this.getResources();
        int id = res.getIdentifier("p" + n % 12, "drawable", this.getPackageName());
        imageView.setImageResource(id);
        n++;
    }
}

• 圖片資源：res\p0~p11