需要帮助才能指望向左或向右滑动

Question

我是Android编程的新手，我正在尝试向左或向右滑动执行计数。

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

当我从左向右滑动时，它会将整数 - 计算为1而不会低于1.

注意：我不是在谈论循环;我想要的是当我每次刷它增加或减少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的值。它没有显示1到10之间的任何值。

我需要帮助来纠正我的代码。

Answer 1

再次检查您的代码：

见这里：

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始终为1，因此显示值为1。

同样在这里：

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始终为10，因此显示值为10。

这两个是您的代码未显示介于1到10之间的其他值的原因。

Answer 2

我得到了答案：

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 = 1;

    @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 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 == 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 > 3) {
                    b = 3;
                }

                //
            }

            break;
        }
        }
        return false;
    }
}

Answer 3

使用switch语句（几乎不显着）有效地提高（每一点帮助）。

默认是如果没有一个案例匹配。

if (x1 < x2) {
b--;

switch(b){
case 1:
TextView tv = (TextView) findViewById(R.id.textView1);
tv.setText("1");
       break;
case 2:
TextView tv = (TextView) findViewById(R.id.textView1);
tv.setText("2");
       break;
case 3:
TextView tv = (TextView) findViewById(R.id.textView1);
tv.setText("3");
       break;
case 4:
TextView tv = (TextView) findViewById(R.id.textView1);
tv.setText("4");
       break;
case 5:
TextView tv = (TextView) findViewById(R.id.textView1);
tv.setText("5");
       break;
case 6:
TextView tv = (TextView) findViewById(R.id.textView1);
tv.setText("6");
       break;
case 7:
TextView tv = (TextView) findViewById(R.id.textView1);
tv.setText("7");
       break;
case 8:
TextView tv = (TextView) findViewById(R.id.textView1);
tv.setText("8");
       break;
case 9:
TextView tv = (TextView) findViewById(R.id.textView1);
tv.setText("9");
       break;
case 10:
TextView tv = (TextView) findViewById(R.id.textView1);
tv.setText("10");
       break;
default:
if (b < 1) {
b = 1;
}

}

}