如何实现SeekBar

Question

我想实现一个滑块，它基本上是两条线，一条垂直线和一条水平线，交叉点触摸屏幕。我设法制作一个，但我必须提出问题：

滑块不是很平滑，当我移动手指时有轻微的延迟
如果我放置两个滑块，它不是多点触控，我想同时使用它们

以下是代码：

public class Slider extends View {

    private Controller controller = new Controller();
    private boolean initialisedSlider;
    private int sliderWidth, sliderHeight;
    private Point pointStart;
    private Paint white;
    private int mode;

    final static int VERTICAL = 0, HORIZONTAL = 1, BOTH = 2;

    public Slider(Context context) {
        super(context);
        setFocusable(true);    
        // TODO Auto-generated constructor stub
    }
    public Slider(Context context, AttributeSet attrs) {
        super(context, attrs);     
        setFocusable(true);    
        pointStart = new Point();
        initialisedSlider = false;   
        mode = Slider.BOTH;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if(!initialisedSlider) {
            initialisedSlider = true;
            sliderWidth = getMeasuredWidth();
            sliderHeight = getMeasuredHeight();

            pointStart.x = (int)(sliderWidth/2.0);
            pointStart.y = (int)(sliderHeight/2.0);
            controller = new Controller(pointStart, 3);

            white = new Paint();
            white.setColor(0xFFFFFFFF);
        }

        canvas.drawLine(controller.getCoordX(),0,
                        controller.getCoordX(),sliderHeight, 
                        white);
        canvas.drawLine(0, controller.getCoordY(), 
                        sliderWidth, controller.getCoordY(), 
                        white);

    }

    public boolean onTouchEvent(MotionEvent event) {
        int eventaction = event.getAction();     
        int X = (int)event.getX(); 
        int Y = (int)event.getY(); 
        switch (eventaction) { 
        case MotionEvent.ACTION_DOWN:
            if(isInBounds(X,Y)) {
                updateController(X, Y);
            }
            break;
        case MotionEvent.ACTION_MOVE:
            if(isInBounds(X,Y)) {
                updateController(X, Y);
            }
            break;
        case MotionEvent.ACTION_UP:
            if(isInBounds(X,Y)) {
                updateController(X, Y);
            }
            break;
        }
        invalidate();  
        return true; 
    }

    private boolean isInBounds(int x, int y) {
        return ((x<=(sliderWidth)) && (x>=(0)) 
                 && (y<=(sliderHeight)) && (y>=(0)));
    }
    private void updateController(int x, int y) {
        switch(mode) {
        case Slider.HORIZONTAL:
            controller.setCoordX(x);
            break;
        case Slider.VERTICAL:
            controller.setCoordY(y);
            break;
        case Slider.BOTH:
            controller.setCoordX(x);
            controller.setCoordY(y);
            break;
        }
    }

    private class Controller {
        private int coordX, coordY;
        Controller() {

        }
        Controller(Point point, int width) {
            setCoordX(point.x);
            setCoordY(point.y);
        }
        public void setCoordX(int coordX) {
            this.coordX = coordX;
        }
        public int getCoordX() {
            return coordX;
        }
        public void setCoordY(int coordY) {
            this.coordY = coordY;
        }
        public int getCoordY() {
            return coordY;
        }
    }
}

XML文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />
    <com.android.lasttest.Slider 
        android:id="@+id/slider"
        android:layout_width="100dp" 
        android:layout_height="100dp" 
        android:layout_gravity="center_horizontal" 
        android:adjustViewBounds="true"/>
    <com.android.lasttest.Slider 
        android:id="@+id/slider"
        android:layout_width="150dp" 
        android:layout_height="150dp" 
        android:layout_gravity="center_horizontal" 
        android:adjustViewBounds="true"/>
    <com.android.lasttest.Slider 
        android:id="@+id/slider"
        android:layout_width="200dp" 
        android:layout_height="200dp" 
        android:layout_gravity="center_horizontal" 
        android:adjustViewBounds="true"/>

</LinearLayout>

Answer 1

Android提供水平滑块

http://developer.android.com/reference/android/widget/SeekBar.html

并实现OnSeekBarChangeListener

http://developer.android.com/reference/android/widget/SeekBar.OnSeekBarChangeListener.html

如果您想要垂直Seekbar，请点击此链接

http://hoodaandroid.blogspot.in/2012/10/vertical-seek-bar-or-slider-in-android.html

Answer 2

如何实现SeekBar

将SeekBar添加到您的布局

max

注释

100是搜索栏可以访问的最高值。默认值为0。最低为min。 xml 0-100值仅在API 26中提供，但您可以通过编程方式将progress范围转换为早期版本所需的范围。
android:rotation="270"是滑点的初始位置（称为＆＃34;拇指＆＃34;）。
对于垂直SeekBar，请使用public class MainActivity extends AppCompatActivity { TextView tvProgressLabel; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // set a change listener on the SeekBar SeekBar seekBar = findViewById(R.id.seekBar); seekBar.setOnSeekBarChangeListener(seekBarChangeListener); int progress = seekBar.getProgress(); tvProgressLabel = findViewById(R.id.textView); tvProgressLabel.setText("Progress: " + progress); } SeekBar.OnSeekBarChangeListener seekBarChangeListener = new SeekBar.OnSeekBarChangeListener() { @Override public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { // updated continuously as the user slides the thumb tvProgressLabel.setText("Progress: " + progress); } @Override public void onStartTrackingTouch(SeekBar seekBar) { // called when the user first touches the SeekBar } @Override public void onStopTrackingTouch(SeekBar seekBar) { // called after the user finishes moving the SeekBar } }; }。

侦听代码中的更改

onStopTrackingTouch

注释

如果您在用户移动搜索栏时不需要进行任何更新，那么您只需更新AppDomain.CurrentDomain.SetupInformation.ConfigurationFile中的用户界面。

另见

SeekBar Tutorial With Example In Android Studio

Answer 3

供将来的读者使用！

从material components android 1.2.0-alpha01开始，您将拥有slider组件

例如：

<com.google.android.material.slider.Slider
        android:id="@+id/slider"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:valueFrom="20f"
        android:valueTo="70f"
        android:stepSize="10" />

在Android中实现滑块（SeekBar）

3 个答案:

如何实现SeekBar

将SeekBar添加到您的布局

侦听代码中的更改

另见