Question

当我尝试运行以下代码时，出现错误。模拟器给我这个错误消息，然后app force关闭： 应用程序意外停止。有什么问题？

import edu.chl.dat255.bluebanana.R;
import android.app.Activity;
import android.os.Bundle;
import android.widget.LinearLayout;
import android.widget.TextView;

public class ProMan extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        LinearLayout layout = (LinearLayout) findViewById(R.layout.main);

        TextView t = new TextView(getApplicationContext());
        t.setText("Hello world");
        layout.addView(t);
    }
}

Answer 1

  LinearLayout layout = (LinearLayout) findViewById(R.id.mainLayout);

In your xml file main xml layout android:id="@+id/mainLayout"

Answer 2

您应该在main.xml中为根LinearLayout设置id，如

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@+id/mainLayout">

然后将其引用为

LinearLayout layout = (LinearLayout) findViewById(R.id.mainLayout);

而不是findViewById（R.layout.main）;

Answer 3

您应该在`TextView t上提供布局信息。应提供布局宽度和布局高度。请参阅下面的代码。

LinearLayout.LayoutParams params = 
    new LinearLayout.LayoutParams( 
       ViewGroup.LayoutParams.WRAP_CONTENT, 
       ViewGroup.LayoutParams.WRAP_CONTENT, 0.0F);
t.setLayoutParams(tvParams);

layout.addView(t);

Android：Layout.addView（）不起作用

3 个答案: