要实现图片的上下张翻页,代码如下,但是一运行程序就奔溃了:
package com.example.administrator.lab41;
import android.support.v7.app.AppCompatActivity;
import android.media.Image;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.view.View.OnClickListener;
import android.app.Activity;
public class MainActivity extends AppCompatActivity {
ImageView img;
Button btn_last,btn_next;
private int[] imgs={
R.drawable.img1,
R.drawable.img2,
R.drawable.img3,
R.drawable.img4,
};
int index=1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn_last=(Button)findViewById(R.id.btn_last);
btn_next=(Button)findViewById(R.id.btn_next);
btn_last.setOnClickListener(new mClick());
btn_next.setOnClickListener(new mClick());
}
class mClick implements OnClickListener
{
public void onClick(View v)
{
if(v==btn_last)
{
if(index>0&&index<imgs.length)
{
index--;
img.setImageResource(imgs[index]);
}else {index=imgs.length-1;}
}
if(v==btn_next)
{
if(index>0&&index<imgs.length-1)
{
index++;
img.setImageResource(imgs[index]);
}else {index=1;}
}
}
}
}