Question

单击图像按钮时，我正在尝试更改图像。即使没有更改图像的代码，每当我使用onClickListener或尝试设置onClick侦听器时，我的应用程序都会崩溃。我如何解决这个问题我在kitkat api 19上运行app

package com.example.t11;

import android.R.string;
import android.support.v7.app.ActionBarActivity;
import android.content.Intent;



import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageButton;
import android.widget.ImageView;

public class Scene extends ActionBarActivity {

ImageView scene=(ImageView) findViewById(R.id.images);

int i=0;

int[] imgarray =    {R.drawable.i1,R.drawable.i2,R.drawable.i4,R.drawable.i6,R.drawable.i7,R.drawable.i8,R.drawable.i9,R.drawable.i10,R.drawable.i12};

 //Just set one Click listener for the image



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_scene);
    Intent sceneint = getIntent();

    ImageButton left = (ImageButton) findViewById(R.id.left);
    ImageButton right= (ImageButton) findViewById(R.id.right);

    // Left and right button listener creation
    left.setOnClickListener(leftlistener);
    right.setOnClickListener(rightlistener);


}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.scene, menu);
    return true;
}


View.OnClickListener rightlistener = new OnClickListener() {


    public void onClick(View v1) {
        //Increase Counter to move to next Image
    i++;


    scene.setImageResource(imgarray[i]);
    }
};

 View.OnClickListener leftlistener = new OnClickListener() {

     public void onClick(View v) {
        //Increase Counter to move to Previous Image
        i--;


        scene.setImageResource(imgarray[i]);
        }
    };






@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}
}

Answer 1

将侦听器实例化为匿名函数：

 left.setOnClickListener(new OnClickListener() {
 public void onClick(View v) {
    //Increase Counter to move to Previous Image
    i--;


    scene.setImageResource(imgarray[i]);
    }
});

如果由于某种原因想要监听器的引用，那么在使用按钮注册之前尝试实例化并分配监听器。

Android ImageButton Onclick无法正常工作

1 个答案: