Android自定义垂直拖动seekbar进度条

Android自带的SeekBar是水平的，要垂直的，必须自己写一个类，继承SeekBar。

一个简单的垂直SeekBar的例子：

（但是它其实是存在一些问题的。不过要是满足基本需要还是可以凑合的）

package com.example.helloverticalseekbar;

import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.SeekBar;

public class VerticalSeekBar extends SeekBar
{

  public VerticalSeekBar(Context context, AttributeSet attrs, int defStyle)
  {
    super(context, attrs, defStyle);
  }

  public VerticalSeekBar(Context context, AttributeSet attrs)
  {
    super(context, attrs);
  }

  public VerticalSeekBar(Context context)
  {
    super(context);
  }

  @Override
  protected void onSizeChanged(int w, int h, int oldw, int oldh)
  {
    super.onSizeChanged(h, w, oldh, oldw);
  }

  @Override
  protected synchronized void onMeasure(int widthMeasureSpec,
      int heightMeasureSpec)
  {
    super.onMeasure(heightMeasureSpec, widthMeasureSpec);
    setMeasuredDimension(getMeasuredHeight(), getMeasuredWidth());
  }

  @Override
  protected synchronized void onDraw(Canvas canvas)
  {
    canvas.rotate(-90);
    canvas.translate(-getHeight(), 0);
    super.onDraw(canvas);
  }

  @Override
  public boolean onTouchEvent(MotionEvent event)
  {
    if (!isEnabled())
    {
      return false;
    }

    switch (event.getAction())
    {
      case MotionEvent.ACTION_DOWN:
      case MotionEvent.ACTION_MOVE:
      case MotionEvent.ACTION_UP:
        setProgress(getMax()
            - (int) (getMax() * event.getY() / getHeight()));
        onSizeChanged(getWidth(), getHeight(), 0, 0);
        break;

      case MotionEvent.ACTION_CANCEL:
        break;
    }

    return true;
  }

}

Demo中加上一个水平SeekBar作为对比，代码如下：

Activity：

HelloSeekBarActivity

package com.example.helloverticalseekbar;

import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.SeekBar.OnSeekBarChangeListener;

public class HelloSeekBarActivity extends Activity
{
  private SeekBar horiSeekBar = null;
  private TextView horiText = null;

  private VerticalSeekBar verticalSeekBar = null;
  private TextView verticalText = null;

  @Override
  protected void onCreate(Bundle savedInstanceState)
  {
    Log.d(AppConstants.LOG_TAG, "onCreate");
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_hello_seek_bar);

    horiSeekBar = (SeekBar) findViewById(R.id.horiSeekBar);
    horiText = (TextView)findViewById(R.id.horiText);
    horiSeekBar.setOnSeekBarChangeListener(horiSeekBarListener);

    verticalSeekBar = (VerticalSeekBar)findViewById(R.id.verticalSeekBar);
    verticalText = (TextView)findViewById(R.id.verticalText);
    verticalSeekBar.setOnSeekBarChangeListener(verticalSeekBarChangeListener);

  }

  @Override
  public boolean onCreateOptionsMenu(Menu menu)
  {
    getMenuInflater().inflate(R.menu.hello_seek_bar, menu);
    return true;
  }

  private OnSeekBarChangeListener horiSeekBarListener = new OnSeekBarChangeListener()
  {

    @Override
    public void onStopTrackingTouch(SeekBar seekBar)
    {

    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar)
    {

    }

    @Override
    public void onProgressChanged(SeekBar seekBar, int progress,
        boolean fromUser)
    {
      Log.d(AppConstants.LOG_TAG, "Horizontal SeekBar --> onProgressChanged");
      horiText.setText(Integer.toString(progress));

    }
  };

  private OnSeekBarChangeListener verticalSeekBarChangeListener = new OnSeekBarChangeListener()
  {

    @Override
    public void onStopTrackingTouch(SeekBar seekBar)
    {

    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar)
    {

    }

    @Override
    public void onProgressChanged(SeekBar seekBar, int progress,
        boolean fromUser)
    {
      Log.d(AppConstants.LOG_TAG, "Vertical SeekBar --> onProgressChanged");
      verticalText.setText(Integer.toString(progress));

    }
  };

}

布局：

activity_hello_seek_bar.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:paddingBottom="@dimen/activity_vertical_margin"
  android:paddingLeft="@dimen/activity_horizontal_margin"
  android:paddingRight="@dimen/activity_horizontal_margin"
  android:paddingTop="@dimen/activity_vertical_margin"
  tools:context=".HelloSeekBarActivity" >

  <TextView
    android:id="@+id/myTextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:text="@string/hello_world" />

  <SeekBar
    android:id="@+id/horiSeekBar"
    android:layout_width="match_parent"
    android:layout_height="20dp"
    android:layout_below="@id/myTextView" />

  <TextView
    android:id="@+id/horiText"
    android:layout_width="wrap_content"
    android:layout_height="20dp"
    android:layout_below="@id/horiSeekBar"
    android:text="horizontal" />

  <com.example.helloverticalseekbar.VerticalSeekBar
    android:id="@+id/verticalSeekBar"
    android:layout_width="wrap_content"
    android:layout_height="200dp"
    android:layout_below="@id/horiText" />

  <TextView
    android:id="@+id/verticalText"
    android:layout_width="wrap_content"
    android:layout_height="20dp"
    android:layout_below="@id/verticalSeekBar"
    android:text="vertical" />

</RelativeLayout>

运行截图：

一个改进版的SeekBar

package com.example.helloverticalseekbarv2;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.widget.SeekBar;

public class VerticalSeekBar extends SeekBar
{
  private boolean mIsDragging;
  private float mTouchDownY;
  private int mScaledTouchSlop;
  private boolean isInScrollingContainer = false;

  public boolean isInScrollingContainer()
  {
    return isInScrollingContainer;
  }

  public void setInScrollingContainer(boolean isInScrollingContainer)
  {
    this.isInScrollingContainer = isInScrollingContainer;
  }

  /**
   * On touch, this offset plus the scaled value from the position of the
   * touch will form the progress value. Usually 0.
   */
  float mTouchProgressOffset;

  public VerticalSeekBar(Context context, AttributeSet attrs, int defStyle)
  {
    super(context, attrs, defStyle);
    mScaledTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();

  }

  public VerticalSeekBar(Context context, AttributeSet attrs)
  {
    super(context, attrs);
  }

  public VerticalSeekBar(Context context)
  {
    super(context);
  }

  @Override
  protected void onSizeChanged(int w, int h, int oldw, int oldh)
  {

    super.onSizeChanged(h, w, oldh, oldw);

  }

  @Override
  protected synchronized void onMeasure(int widthMeasureSpec,
      int heightMeasureSpec)
  {
    super.onMeasure(heightMeasureSpec, widthMeasureSpec);
    setMeasuredDimension(getMeasuredHeight(), getMeasuredWidth());
  }

  @Override
  protected synchronized void onDraw(Canvas canvas)
  {
    canvas.rotate(-90);
    canvas.translate(-getHeight(), 0);
    super.onDraw(canvas);
  }

  @Override
  public boolean onTouchEvent(MotionEvent event)
  {
    if (!isEnabled())
    {
      return false;
    }

    switch (event.getAction())
    {
      case MotionEvent.ACTION_DOWN:
        if (isInScrollingContainer())
        {

          mTouchDownY = event.getY();
        }
        else
        {
          setPressed(true);

          invalidate();
          onStartTrackingTouch();
          trackTouchEvent(event);
          attemptClaimDrag();

          onSizeChanged(getWidth(), getHeight(), 0, 0);
        }
        break;

      case MotionEvent.ACTION_MOVE:
        if (mIsDragging)
        {
          trackTouchEvent(event);

        }
        else
        {
          final float y = event.getY();
          if (Math.abs(y - mTouchDownY) > mScaledTouchSlop)
          {
            setPressed(true);

            invalidate();
            onStartTrackingTouch();
            trackTouchEvent(event);
            attemptClaimDrag();

          }
        }
        onSizeChanged(getWidth(), getHeight(), 0, 0);
        break;

      case MotionEvent.ACTION_UP:
        if (mIsDragging)
        {
          trackTouchEvent(event);
          onStopTrackingTouch();
          setPressed(false);

        }
        else
        {
          // Touch up when we never crossed the touch slop threshold
          // should
          // be interpreted as a tap-seek to that location.
          onStartTrackingTouch();
          trackTouchEvent(event);
          onStopTrackingTouch();

        }
        onSizeChanged(getWidth(), getHeight(), 0, 0);
        // ProgressBar doesn't know to repaint the thumb drawable
        // in its inactive state when the touch stops (because the
        // value has not apparently changed)
        invalidate();
        break;
    }
    return true;

  }

  private void trackTouchEvent(MotionEvent event)
  {
    final int height = getHeight();
    final int top = getPaddingTop();
    final int bottom = getPaddingBottom();
    final int available = height - top - bottom;

    int y = (int) event.getY();

    float scale;
    float progress = 0;

    // 下面是最小值
    if (y > height - bottom)
    {
      scale = 0.0f;
    }
    else if (y < top)
    {
      scale = 1.0f;
    }
    else
    {
      scale = (float) (available - y + top) / (float) available;
      progress = mTouchProgressOffset;
    }

    final int max = getMax();
    progress += scale * max;

    setProgress((int) progress);

  }

  /**
   * This is called when the user has started touching this widget.
   */
  void onStartTrackingTouch()
  {
    mIsDragging = true;
  }

  /**
   * This is called when the user either releases his touch or the touch is
   * canceled.
   */
  void onStopTrackingTouch()
  {
    mIsDragging = false;
  }

  private void attemptClaimDrag()
  {
    ViewParent p = getParent();
    if (p != null)
    {
      p.requestDisallowInterceptTouchEvent(true);
    }
  }

  @Override
  public synchronized void setProgress(int progress)
  {

    super.setProgress(progress);
    onSizeChanged(getWidth(), getHeight(), 0, 0);

  }

}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。