Question

I am a beginner in android development are, to be exact, in development are.
I was starting to learn developing for android, and wanted to do this exercise:
write a small program to change the brightness to three different levels: current-low-high.
and after writing my code and everything, I cannot get it to run, every time I run it, the FORCE CLOSE comes up. PLEASE HELP ME TO FIND MY ERROR. 🙁

my code:

package com.dummies.android.helloandroid;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;

public class MainActivity extends Activity {
    /** Called when the activity is first created. */
     // MY BRIGHTNESS VARIABLES


 WindowManager.LayoutParams lp = getWindow().getAttributes();
 float fb = lp.screenBrightness;
 float lb = 0;
 float hb = 1;
 //////////////////////////////////////////////////////////////////////////
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


   // MY CODE FROM HERE DOWN

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

    button1.setOnClickListener(new View.OnClickListener() {

    public void onClick(View v) {

        if(lp.screenBrightness==fb) {
            lp.screenBrightness=lb;
            getWindow().setAttributes(lp);
        }
        if(lp.screenBrightness==lb){
            lp.screenBrightness=hb;
            getWindow().setAttributes(lp);
        }
        if(lp.screenBrightness==hb){
            lp.screenBrightness=fb;
            getWindow().setAttributes(lp);
        }

    }
} );
    //////////////////////////////////////////////




}

}

please help ME 🙁 what do I need to do to get it to work?

Answer 1

Anyway, I do spot one error that might be the potential problem.

WindowManager.LayoutParams lp = getWindow().getAttributes();

This line is your potential trouble. Move this to After you do setContentView(R.layout.main);

You can’t do getWindow().getAttributes() before window is constructed.

Thus, your code will become

package com.dummies.android.helloandroid;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;

public class MainActivity extends Activity {
    /** Called when the activity is first created. */
     // MY BRIGHTNESS VARIABLES


 WindowManager.LayoutParams lp;
 float fb;
 float lb = 0;
 float hb = 1;
 //////////////////////////////////////////////////////////////////////////
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    lp = getWindow().getAttributes();
    fb = lp.screenBrightness;

   // MY CODE FROM HERE DOWN

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

    button1.setOnClickListener(new View.OnClickListener() {

    public void onClick(View v) {

        if(lp.screenBrightness==fb) {
            lp.screenBrightness=lb;
            getWindow().setAttributes(lp);
        }
        if(lp.screenBrightness==lb){
            lp.screenBrightness=hb;
            getWindow().setAttributes(lp);
        }
        if(lp.screenBrightness==hb){
            lp.screenBrightness=fb;
            getWindow().setAttributes(lp);
        }

    }
} );
    //////////////////////////////////////////////




}

}