java - 如何用java在布局中放置图像？安卓

Question

我在drawable-mdpi文件夹中有一个名为c1.png的图像。我想通过 Java 将其布局如下:

package ...;

import android.os.Bundle;
//import android.provider.MediaStore.Images;
import android.app.ActionBar.LayoutParams;
import android.app.Activity;
import android.view.Menu;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;

public class MainActivity extends Activity 
{

    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        LinearLayout layout = (LinearLayout)findViewById(getCurrentFocus().getId() );

        ImageView img = new ImageView(this);
        ViewGroup.LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
        img.setLayoutParams(lp);
        img.setImageDrawable(getResources().getDrawable(R.drawable.c1));
        layout.addView(img);
        setContentView(layout);//Doesn't matter, if it's commented or not. The error still exists.
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) 
    {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }


}

启动时我得到:“不幸的是，%application_name 已停止”。我看到很多例子，在 id 参数中使用 R.id.*，但它也停止了(如 R.id.linearLayout1)，或者 R 没有这样的常数(如 R.id.c1)。我怎样才能做到这一点？

Answer 1

import android.app.Activity;
import android.view.Menu;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;

public class MainActivity extends Activity 
{

@Override
protected void onCreate(Bundle savedInstanceState) 
{

    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    LinearLayout layout = (LinearLayout)findViewById(R.id.layoutID ); // //layoutID is id of the linearLayout that defined in your main.xml file

    ImageView img = new ImageView(this);
    ViewGroup.LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    img.setLayoutParams(lp);
    img.setBackgroundResource(R.drawable.c1);
    layout.addView(img);

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

希望这有帮助。