Add a Button dynamically to a LinearLayout in Android

Question

I am working on a project that needs to add buttons dynamically. But whenever I run my application the application force closes. I've learned that the problem is when I try to add buttons.

package com.Feras.TestProject;
import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.LinearLayout;

public class TestProject extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    setContentView(R.layout.main);
    AddAll();
    // Set Text for the button in the Old Testament



}
public void AddAll() {
    LinearLayout linearLayout = (LinearLayout)findViewById(R.id.layout1);
    Button btn = new Button(this); 
    btn.setText("MyButton"); 
    linearLayout.addView(btn); 


    }
}

Answer 1

try like this:

linearLayout.addView(
                     btn, 
                     new LayoutParams(
                          LayoutParams.WRAP_CONTENT, 
                          LayoutParams.WRAP_CONTENT)
                     );

Answer 2

如果linearLayout为null，则只会发生错误，请确保layout1是R.layout.main的有效项

Answer 3

Try the following in your custom activity class:

this.addContentView(call,
    new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));