android-bitmap创建设置图片

package zhang.decodeFile;

import java.io.File;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

public class decodeFile extends Activity {
private ImageView mImageView;
private Button mButton;
private TextView mTextView;
private String fileName="/data/q2.jpg";
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

mButton = (Button)findViewById(R.id.button1);
mButton.setOnClickListener(new Button.OnClickListener(){

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
mImageView=(ImageView)findViewById(R.id.imageView1);
mTextView=(TextView)findViewById(R.id.TextView1);

File f =  new File(fileName);
if(f.exists()){
Bitmap bm = BitmapFactory.decodeFile(fileName);
mImageView.setImageBitmap(bm);
mTextView.setText(fileName);
}else{
mTextView.setText(fileName+"no");
}

}
});
}
}

<?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:id="@+id/TextView1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
<ImageView android:layout_height="wrap_content" android:src="@drawable/qq" android:id="@+id/imageView1" android:layout_width="wrap_content"></ImageView>
<Button android:text="Button" android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>
</LinearLayout>