Question

在android中，有三个活动。我可以使用下一个按钮转到每个活动，但是当使用上一个按钮从第二个活动返回到第一个活动时，它不会响应上一个按钮。我的三个.java文件是 1. MainActivity.java

   public class MainActivity extends AppCompatActivity {


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

        Button Next = (Button) findViewById(R.id.button1);
        Next.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                Intent myIntent = new Intent(view.getContext(), DisplayMessageActivity.class);
                startActivityForResult(myIntent, 0);
            }
        });

    }
}

DisplayMessageActivity.java

public class DisplayMessageActivity extends AppCompatActivity {

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

Button pre = (Button) findViewById(R.id.button2);
pre.setOnClickListener(new View.OnClickListener() {
    public void onClick(View view) {
        Intent intent = new Intent();
        setResult(RESULT_OK, intent);

    }
});
setContentView(R.layout.activity_display_message);

Button Next = (Button) findViewById(R.id.button3);
Next.setOnClickListener(new View.OnClickListener() {
    public void onClick(View view) {
            Intent myIntent = new Intent(view.getContext(), ThirdActivity.class);
            startActivityForResult(myIntent, 0);
        }
    });
}
}

ThirdActivity.java

public class ThirdActivity extends AppCompatActivity {


@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.third_activity);

Button previous = (Button) findViewById(R.id.button4);
previous.setOnClickListener(new View.OnClickListener() {
    public void onClick(View view) {
        Intent intent = new Intent();
        setResult(RESULT_OK, intent);
        finish();
    }

    });
}
}

Answer 1

首先，java变量应该从小写字母开始，如果它不是常量变量（参见Variables Java Documentation）。

要解决您的问题，您应该在finish() setResult(RESULT_OK, intent)之后致电DisplayMessageActivity.java。同时删除setContentView(R.layout.activity_display_message)的第二次调用。

    public class DisplayMessageActivity extends AppCompatActivity {

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

        Button pre = (Button) findViewById(R.id.button2);
        pre.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                Intent intent = new Intent();
                setResult(RESULT_OK, intent);
                finish(); //add this

            }
        });
        //setContentView(R.layout.activity_display_message);//remove this

        Button next = (Button) findViewById(R.id.button3);//rename 'Next' to 'next'
        next.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                Intent myIntent = new Intent(view.getContext(), ThirdActivity.class);
                startActivityForResult(myIntent, 0);
            }
        });
     }
  }

不能去上一个活动

1 个答案: