将int传递给其他活动会导致奇怪的行为

Question

I am passing 3 ints from MainActivity to main and displaying them in separate Textviews . When I click button to go to next activity, it shows the last passed int in the last textview. Pressing the back button on my smartphone, it resets the last textview to 0 and shows the correct value for the second textview. Then pressing the back button again, it resets the second textview to 0 and shows the correct value for the first textview.

Code inside OnCreate method at MainActivity.java :

            Intent sendX = new Intent(MainActivity.this, main.class);
            sendX.putExtra("x", x);
            startActivity(sendX);
            Intent sendY = new Intent(MainActivity.this, main.class);
            sendY.putExtra("y", y);
            startActivity(sendY);
            Intent sendZ = new Intent(MainActivity.this, main.class);
            sendZ.putExtra("z", z);
            startActivity(sendZ);

Code inside OnCreate method at main.class :

    Intent getX = getIntent();
    x = getX.getIntExtra("x", 0);
    Intent getY = getIntent();
    y = getY.getIntExtra("y", 0);
    Intent getZ = getIntent();
    z = getZ.getIntExtra("z", 0);

    TextView test1 = (TextView)findViewById(R.id.testx);
    test1.setText(Integer.toString(x));
    TextView test2 = (TextView)findViewById(R.id.testy);
    test2.setText(Integer.toString(y));
    TextView test3 = (TextView)findViewById(R.id.testz);
    test3.setText(Integer.toString(z));

Answer 1

You need to read up on how Intents work some more. You're basically starting 3 instances of the same Activity. Do this instead:

Intent intent = new Intent(MainActivity.this, main.class);
intent.putExtra("x", x);
intent.putExtra("y", y);
intent.putExtra("z", z);
startActivity(intent);

and

Intent intent = getIntent();
x = intent.getIntExtra("x", 0);
y = intent.getIntExtra("y", 0);
x = intent.getIntExtra("z", 0);