Toast--报错

Posted 2020-09-18 左手指月的博客

 

Toast的makeText()方法报错
帖上一代码,用Toast来简单处理回调机制.但是Toast的makeText()方法老报错:
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.KeyEvent;
import android.widget.Button;
import android.widget.Toast;

public class MyButton  extends  Button {

public MyButton(Context context, AttributeSet attrs) {
   super(context, attrs);
}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
super.onKeyDown(keyCode, event);
  //就是这里了

Toast toast=Toast.makeText(MyButton.this, "the callBack test", 5000);
toast.show();
return true;
}
}
报错信息：

The method makeText(Context, CharSequence, int) in the type Toast is not applicable for the arguments (MyButton, String, int)

------解决方案--------------------
public class MyButton extends Button {

private Context mContext;

public MyButton(Context context, AttributeSet attrs) {
super(context, attrs);
   mContext = context;
}

Toast toast=Toast.makeText(mContext, "the callBack test", 5000);
toast.show(); 
------解决方案--------------------
第一个参数，使用  getContext() 或者 getApplicationContext()
第三个参数也不正确，应该是   Toast.makeText(getContext(), "the callBack test", Toast.LENGTH_LONG).show();