java - 需要帮助来判断向左或向右滑动

Question

我是 Android 编程新手，我正在尝试在向左或向右滑动时执行计数。

我想要的是，当我从右向左滑动时，它会计算整数 ++ 最多 10 次，但不会超过 10 次。

当我从左向右滑动时，它会将整数 -- 向下计数到 1，而不是低于 1。

注意:我不是在谈论循环；而是在谈论循环。我想要的是当我每次滑动它增加或减少 int 计数时。

我尝试的是:

package com.usd.swipegesture;

import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.widget.TextView;
import android.widget.Toast;

public class Gesture extends Activity {
    float x1, x2;
    float y1, y2;
    static int b;

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

    // onTouchEvent () method gets called when User performs any touch event on
    // screen
    // Method to handle touch event like left to right swap and right to left
    // swap
    public boolean onTouchEvent(MotionEvent touchevent) {
        switch (touchevent.getAction()) {
        // when user first touches the screen we get x and y coordinate
        case MotionEvent.ACTION_DOWN: {
            x1 = touchevent.getX();
            y1 = touchevent.getY();
            break;
        }
        case MotionEvent.ACTION_UP: {
            x2 = touchevent.getX();
            y2 = touchevent.getY();

            // if left to right sweep event on screen
            if (x1 < x2) {
                // Toast.makeText(this, "Left to Right Swap Performed",
                // Toast.LENGTH_LONG).show();

                //
                b--;
                if (b == 1) {
                    b = 1;

                    if (b == 1) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("1");
                    }

                    if (b == 2) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("2");
                    }

                    if (b == 3) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("3");
                    }

                    if (b == 4) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("4");
                    }

                    if (b == 5) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("5");
                    }

                    if (b == 6) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("6");
                    }

                    if (b == 7) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("7");
                    }

                    if (b == 8) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("8");
                    }

                    if (b == 9) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("9");
                    }

                    if (b == 10) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("10");
                    }

                }
                //
            }

            // if right to left sweep event on screen
            if (x1 > x2) {
                // Toast.makeText(this, "Right to Left Swap Performed",
                // Toast.LENGTH_LONG).show();
                //
                b++;
                if (b == 10) {
                    b = 10;

                    if (b == 1) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("1");
                    }

                    if (b == 2) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("2");
                    }

                    if (b == 3) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("3");
                    }

                    if (b == 4) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("4");
                    }

                    if (b == 5) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("5");
                    }

                    if (b == 6) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("6");
                    }

                    if (b == 7) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("7");
                    }

                    if (b == 8) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("8");
                    }

                    if (b == 9) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("9");
                    }

                    if (b == 10) {
                        TextView tv = (TextView) findViewById(R.id.textView1);
                        tv.setText("10");
                    }
                }
                //
            }

            break;
        }
        }
        return false;
    }
}

但它只显示 1 和 10 值。它没有显示 1 到 10 之间的任何值。

我需要帮助来更正我的代码。

Answer 1

再次检查您的代码:

请参阅此处:

if (b == 1) {
     b = 1; // b is now 1

     if (b == 1) { // if b is 1 then do this 
          TextView tv = (TextView) findViewById(R.id.textView1);
          tv.setText("1");
     }
     .....

b is always 1, hence it is showing value 1.

这里也类似:

if (b == 10) {
      b = 10; // b is now 10
      ......
      if (b == 10) { // if b is 10 then do this 
          TextView tv = (TextView) findViewById(R.id.textView1);
          tv.setText("10");
      }

b is always 10, hence it is showing value 10.

这两个原因是您的代码未显示 1 到 10 之间的其他值的原因。