setOnClickListener 错误 - 无法解析符号

Question

我想创建一个按钮，单击该按钮时，它将显示另一个意图。

这是代码：

   <Button
    android:text="Bine ati venit!"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/button1"
    android:background="#479fc7"
    android:textSize="40dp"
    android:textColor="@color/colorPrimaryDark"
    android:textStyle="normal|bold|italic"
    android:textAllCaps="false"
    android:fontFamily="casual"
    android:onClick="next_page"/>

以及来自 .java 类：

    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_welcome);
}

Button button = (Button) findViewById(R.id.button1);

button.setOnClickListener( new View.OnClickListener()
{
    public void onClick (View v){
    next_page(v);
}
});

public void next_page(View v) {
    Intent intent = new Intent(this, MapsActivity.class);
    startActivity(intent);
}

我收到错误：“无法解析符号‘setOnClickListener’”、“变量 onClick 从未使用”、“；预期”...

Answer 1

// 您必须将键入的代码移至类方法中并按如下方式工作

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // Find the View that shows the numbers category
        TextView numbers = (TextView) findViewById(R.id.numbers);

// Set a click listener on that View
        numbers.setOnClickListener(new View.OnClickListener() {
            // The code in this method will be executed when the numbers View is clicked on.
            @Override
            public void onClick(View view) {
                Intent numbersIntent = new Intent(MainActivity.this, NumberActivity.class);
                startActivity(numbersIntent);
            }
        });
    }