Question

mTextView01=(TextView) findViewById(R.id.myTextView01); //The method findViewById(int) in the type.

package com.example.helloworld;
import android.os.Bundle;
import android.app.Activity;
import android.widget.TextView;
public class MainActivity extends Activity {
private TextView mTextView01;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

TextView mTextView01 = (TextView) findViewById(R.id.myTextView01);
String str_2="Welcome to the java world. ";
mTextView01.setText(str_2);
}
}
The method findViewById(int) in the type Activity is not applicable for the arguments (Object)

Answer 1

检查一下你的布局文件里的 myTextView01，这个组件是否正确。从错误信息来看R.id.myTextView01被认为是Object而不是int类型。如果方便可以把你的布局文件贴出来。

Answer 2

参数类型不对R.id.myTextView01是个obj类型~findViewById(int)是要求int型的