每个按钮单击可更改文本视图

Question

i coded this lines to change textview1 Continuous when user clicked button but it sucks at value 1 in output why :\\

public class dobeyti extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_dobeyti);
   final TextView tView;
    Button mButton;

    tView = (TextView)findViewById(R.id.textView1);
    mButton = (Button)findViewById(R.id.button);
    assert mButton != null;
    mButton.setOnClickListener(new View.OnClickListener() {


        @Override
        public void onClick(View v) {
            int num = 0;
            num++;


           tView.setText(Integer.toString(num));
        }
    });

    }
}

Answer 1

Becuase you defined the num value inside the onclick method so it will be reassigned to 0 every time.

Just put int num=0 outside the method like below:

@Override
protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_dobeyti);
   final TextView tView;
Button mButton;

tView = (TextView)findViewById(R.id.textView1);
mButton = (Button)findViewById(R.id.button);
assert mButton != null;
mButton.setOnClickListener(new    View.OnClickListener() {

    int num = 0;
    @Override
    public void onClick(View v) {

        num++;


       tView.setText(Integer.toString(num));
    }
});

}
}

Answer 2

Move int num = 0; outside OnClickListener. Every time you click button value on variable num is set to 0 -> increased to 1 and set as text, that is why it stuck at 1.

int num = 0;
mButton.setOnClickListener(new View.OnClickListener() {


    @Override
    public void onClick(View v) {
        num++;
       tView.setText(Integer.toString(num));
    }
});

}

}