Android学习路之ProgressBar

ProgressBar(进度条)

1、系统默认进度条使用实例：

<LinearLayout 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:orientation="vertical"    tools:context=".MainActivity">    <!-- 系统提供的圆形进度条,依次是大中小 -->    <ProgressBar        style="@android:style/Widget.ProgressBar.Small"        android:layout_width="wrap_content"        android:layout_height="wrap_content" />    <ProgressBar        android:layout_width="wrap_content"        android:layout_height="wrap_content" />    <ProgressBar        style="@android:style/Widget.ProgressBar.Large"        android:layout_width="wrap_content"        android:layout_height="wrap_content" />    <!--系统提供的水平进度条-->    <ProgressBar        style="@android:style/Widget.ProgressBar.Horizontal"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:max="100"        android:progress="18" />    <ProgressBar        style="@android:style/Widget.ProgressBar.Horizontal"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_marginTop="10dp"        android:indeterminate="true" /></LinearLayout>

效果展示：

2.使用动画来替代圆形进度条

使用一套连续图片，形成一个帧动画，当需要进度图的时候，让动画可见，不需要的时候让动画不可见即可

实现步骤：在res目录下新建一个:anim文件件，然后创建amin_pgbar.xml的资源文件：

    <?xml version="1.0" encoding="utf-8"?><animation-list xmlns:android="http://schemas.android.com/apk/res/android"android:oneshot="false" ><item    android:drawable="@drawable/loading_01"    android:duration="200"/><item    android:drawable="@drawable/loading_02"    android:duration="200"/><item    android:drawable="@drawable/loading_03"    android:duration="200"/><item    android:drawable="@drawable/loading_04"    android:duration="200"/><item    android:drawable="@drawable/loading_05"    android:duration="200"/><item    android:drawable="@drawable/loading_06"    android:duration="200"/><item    android:drawable="@drawable/loading_07"    android:duration="200"/><item    android:drawable="@drawable/loading_08"    android:duration="200"/><item    android:drawable="@drawable/loading_09"    android:duration="200"/><item    android:drawable="@drawable/loading_10"    android:duration="200"/><item    android:drawable="@drawable/loading_11"    android:duration="200"/><item    android:drawable="@drawable/loading_12"    android:duration="200"/></animation-list> 

接着写个布局文件，里面仅仅有一个ImageView即可，用于显示进度条，把src设置为上述drawable资源即可！最后到MainActivity.java

public class MainActivity extends AppCompatActivity {    private ImageView img_pgbar;    private AnimationDrawable ad;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        img_pgbar = (ImageView) findViewById(R.id.img_pgbar);        ad = (AnimationDrawable) img_pgbar.getDrawable();        img_pgbar.postDelayed(new Runnable() {            @Override            public void run() {                ad.start();            }        }, 100);    }}效果展示：

3.自定义圆形进度条

public class CirclePgBar extends View {    private Paint mBackPaint;    private Paint mFrontPaint;    private Paint mTextPaint;    private float mStrokeWidth = 50;    private float mHalfStrokeWidth = mStrokeWidth / 2;    private float mRadius = 200;    private RectF mRect;    private int mProgress = 0;    //目标值，想改多少就改多少    private int mTargetProgress = 90;    private int mMax = 100;    private int mWidth;    private int mHeight;    public CirclePgBar(Context context) {        super(context);        init();    }    public CirclePgBar(Context context, AttributeSet attrs) {        super(context, attrs);        init();    }    public CirclePgBar(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        init();    }    //完成相关参数初始化    private void init() {        mBackPaint = new Paint();        mBackPaint.setColor(Color.WHITE);        mBackPaint.setAntiAlias(true);        mBackPaint.setStyle(Paint.Style.STROKE);        mBackPaint.setStrokeWidth(mStrokeWidth);        mFrontPaint = new Paint();        mFrontPaint.setColor(Color.GREEN);        mFrontPaint.setAntiAlias(true);        mFrontPaint.setStyle(Paint.Style.STROKE);        mFrontPaint.setStrokeWidth(mStrokeWidth);        mTextPaint = new Paint();        mTextPaint.setColor(Color.GREEN);        mTextPaint.setAntiAlias(true);        mTextPaint.setTextSize(80);        mTextPaint.setTextAlign(Paint.Align.CENTER);    }    //重写测量大小的onMeasure方法和绘制View的核心方法onDraw()    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        mWidth = getRealSize(widthMeasureSpec);        mHeight = getRealSize(heightMeasureSpec);        setMeasuredDimension(mWidth, mHeight);    }    @Override    protected void onDraw(Canvas canvas) {        initRect();        float angle = mProgress / (float) mMax * 360;        canvas.drawCircle(mWidth / 2, mHeight / 2, mRadius, mBackPaint);        canvas.drawArc(mRect, -90, angle, false, mFrontPaint);        canvas.drawText(mProgress + "%", mWidth / 2 + mHalfStrokeWidth, mHeight / 2 + mHalfStrokeWidth, mTextPaint);        if (mProgress < mTargetProgress) {            mProgress += 1;            invalidate();        }    }    public int getRealSize(int measureSpec) {        int result = 1;        int mode = MeasureSpec.getMode(measureSpec);        int size = MeasureSpec.getSize(measureSpec);        if (mode == MeasureSpec.AT_MOST || mode == MeasureSpec.UNSPECIFIED) {            //自己计算            result = (int) (mRadius * 2 + mStrokeWidth);        } else {            result = size;        }        return result;    }    private void initRect() {        if (mRect == null) {            mRect = new RectF();            int viewSize = (int) (mRadius * 2);            int left = (mWidth - viewSize) / 2;            int top = (mHeight - viewSize) / 2;            int right = left + viewSize;            int bottom = top + viewSize;            mRect.set(left, top, right, bottom);        }    }}