定义keyPreference以使可见和不可见的imageView

Question

I have three Activities with one button in each of them. Act1 with btn1, Act2 with btn2, and Act3 with btn3. I have another Activity as MainActivity with three imageViews: ImageView1, imageView2 and imageView3, all of which are initially invisible. I want it so when I click on btn1 in act1, imageView1 in MainActivity will be visible and when click on btn1 again, imageView1 will be invisible again. And similarly for imageView2 and imageView3. I have this code so far:

Activity1

public class Activity1 extends AppCompatActivity{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity1);

Button btn1 = (Button) findViewById(R.id.btn1);
btn1.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        String visibilityStr = PublicSharedPreferences.getDefaults("keyVisibility1", getApplicationContext());

        if (visibilityStr != null) {
            if (visibilityStr.equals("0")) {
                Toast.makeText(act1.this, "it visibled", Toast.LENGTH_SHORT).show();
                visibilityStr = "1";
btn1.setImageResource(R.mipmap.img1);

            } else {
                visibilityStr = "0";
                Toast.makeText(act1.this, "it invisibled", Toast.LENGTH_SHORT).show();
btn1.setImageResource(R.mipmap.img2);

            }
        } else {
            visibilityStr = "1";
            Toast.makeText(act1.this, "it visibled", Toast.LENGTH_SHORT).show();
btn1.setImageResource(R.mipmap.img1);

        }

        PublicSharedPreferences.setDefaults("keyVisibility1", visibilityStr, getApplicationContext());

    }
});
}





Activity2

public class Activity2 extends AppCompatActivity{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity2);


Button btn1 = (Button) findViewById(R.id.btn2);
btn1.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        String visibilityStr = PublicSharedPreferences.getDefaults("keyVisibility2", getApplicationContext());

        if (visibilityStr != null) {
            if (visibilityStr.equals("0")) {
                Toast.makeText(act2.this, "it visibled", Toast.LENGTH_SHORT).show();
btn2.setImageResource(R.mipmap.img1);

                visibilityStr = "1";
            } else {
                visibilityStr = "0";
                Toast.makeText(act2.this, "it invisibled", Toast.LENGTH_SHORT).show();
btn2.setImageResource(R.mipmap.img2);

            }
        } else {
            visibilityStr = "1";
            Toast.makeText(act2.this, "it visibled", Toast.LENGTH_SHORT).show();
btn2.setImageResource(R.mipmap.img1);

        }

        PublicSharedPreferences.setDefaults("keyVisibility2", visibilityStr, getApplicationContext());

    }
});
}



Activity3

public class Activity3 extends AppCompatActivity{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity3);

Button btn1 = (Button) findViewById(R.id.btn3);
btn1.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        String visibilityStr = PublicSharedPreferences.getDefaults("keyVisibility3", getApplicationContext());

        if (visibilityStr != null) {
            if (visibilityStr.equals("0")) {
                Toast.makeText(act3.this, "it visibled", Toast.LENGTH_SHORT).show();
Btn3.setImageResource(R.mipmap.img1);

                visibilityStr = "1";
            } else {
                visibilityStr = "0";
                Toast.makeText(act3.this, "it invisibled", Toast.LENGTH_SHORT).show();
btn3.setImageResource(R.mipmap.img2);

            }
        } else {
            visibilityStr = "1";
            Toast.makeText(act3.this, "it visibled", Toast.LENGTH_SHORT).show();
btn3.setImageResource(R.mipmap.img1);

        }

        PublicSharedPreferences.setDefaults("keyVisibility3", visibilityStr, getApplicationContext());
    }
});
}

MainActivity with three imageViews:

        ImageView imgView1 = (ImageView) findViewById(R.id.imgView1);
String visibilityStr= PublicSharedPreferences.getDefaults("keyVisibility1", getApplicationContext());

if (visibilityStr.equals("0"))
    imgView1.setVisibility(View.INVISIBLE);
else
    imgView1.setVisibility(View.VISIBLE);


ImageView imgView2 = (ImageView) findViewById(R.id.imgView2);
String visibilityStr= PublicSharedPreferences.getDefaults("keyVisibility2", getApplicationContext());

if (visibilityStr.equals("0"))
    imgView2.setVisibility(View.INVISIBLE);
else
    imgView2.setVisibility(View.VISIBLE);



ImageView imgView3 = (ImageView) findViewById(R.id.imgView3);
String visibilityStr= PublicSharedPreferences.getDefaults("keyVisibility3", getApplicationContext());

if (visibilityStr.equals("0"))
    imgView3.setVisibility(View.INVISIBLE);
else
    imgView3.setVisibility(View.VISIBLE);

and SharedPreferences class:

 public class PublicSharedPreferences {



    public static void setDefaults(String key, String value, Context context) {
        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
        SharedPreferences.Editor editor = prefs.edit();
        editor.putString(key, value);
        editor.commit();
    }

    public static String getDefaults(String key, Context context) {
        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
        return preferences.getString(key, null);
    }


}

They work well. But the problem is that when I click on btn1, all imageViews in MainActivity change (become visible or invisible) or when I click on btn3, all imageViews change. I want btn1 just changes imageView1 and btn2 just changes imageView2 and btn3 just changes imageView3, instead of one of the buttons changing all of the imageViews. i think the problem is that i defined just one key Preference for all of them. but i dont know how i can define special key for each one. how can i do that? please change the codes and write them again. tnx.

Answer 1

You use 1 variable for all the 3 if!

make different variable for each activity / imageview

  ImageView imgView1 = (ImageView) findViewById(R.id.imgView1); //keyVisibility1 String visibilityStr= PublicSharedPreferences.getDefaults("keyVisibility1", getApplicationContext()); if (visibilityStr.equals("0")) imgView1.setVisibility(View.INVISIBLE); else imgView1.setVisibility(View.VISIBLE); ImageView imgView2 = (ImageView) findViewById(R.id.imgView2); //keyVisibility2 visibilityStr= PublicSharedPreferences.getDefaults("keyVisibility2", getApplicationContext()); if (visibilityStr.equals("0")) imgView2.setVisibility(View.INVISIBLE); else imgView2.setVisibility(View.VISIBLE); ImageView imgView3 = (ImageView) findViewById(R.id.imgView3); //keyVisibility3 visibilityStr= PublicSharedPreferences.getDefaults("keyVisibility3", getApplicationContext()); if (visibilityStr.equals("0")) imgView3.setVisibility(View.INVISIBLE); else imgView3.setVisibility(View.VISIBLE); 

(also change in each activity to keyVisibility1, keyVisibility2 and keyVisibility3)

Answer 2

make three static variable in separate class name Constant. and initialize them with false

public class Constant() {
    public static Boolean firstButton = false;
    public static Boolean secondButton = false;
    public static Boolean thirdButton = false;
}

now when you click on btn1, of your activity1, do this

btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Constant.firstButton = !Constant.firstButton;
                // start new Activity
            }
        });

now in your other activity. in your onCreateMethode just do that

imageView1.setVisibility(Constant.firstButton ? View.Visible: View.Gone);