Android 简单案例：onSaveInstanceState 和 onRestoreInstanceState

import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.ImageView; import android.widget.TextView;  public final class MultiRes extends Activity {      private int mCurrentPhotoIndex = 0;     private int[] mPhotoIds = new int[] { R.drawable.sample_0,             R.drawable.sample_1, R.drawable.sample_2, R.drawable.sample_3,             R.drawable.sample_4, R.drawable.sample_5, R.drawable.sample_6,             R.drawable.sample_7 };      /** Called when the activity is first created. */     @Override     public void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.main);          showPhoto(mCurrentPhotoIndex);          // Handle clicks on the 'Next' button.         Button nextButton = (Button) findViewById(R.id.next_button);         nextButton.setOnClickListener(new View.OnClickListener() {             public void onClick(View v) {                 mCurrentPhotoIndex = (mCurrentPhotoIndex + 1)                         % mPhotoIds.length;                 showPhoto(mCurrentPhotoIndex);             }         });     }      @Override     protected void onSaveInstanceState(Bundle outState) {         outState.putInt("photo_index", mCurrentPhotoIndex);         super.onSaveInstanceState(outState);     }      @Override     protected void onRestoreInstanceState(Bundle savedInstanceState) {         mCurrentPhotoIndex = savedInstanceState.getInt("photo_index");         showPhoto(mCurrentPhotoIndex);         super.onRestoreInstanceState(savedInstanceState);     }      private void showPhoto(int photoIndex) {         ImageView imageView = (ImageView) findViewById(R.id.image_view);         imageView.setImageResource(mPhotoIds[photoIndex]);          TextView statusText = (TextView) findViewById(R.id.status_text);         statusText.setText(String.format("%d/%d", photoIndex + 1,                 mPhotoIds.length));     } }