Android編程實(shí)現(xiàn)的手寫板和涂鴉功能

更新時(shí)間：2018年01月15日 12:01:03 作者：shineflowers

這篇文章主要介紹了Android編程實(shí)現(xiàn)的手寫板和涂鴉功能,涉及Android界面布局及圖形繪制功能相關(guān)實(shí)現(xiàn)技巧,需要的朋友可以參考下

本文實(shí)例講述了Android編程實(shí)現(xiàn)的手寫板和涂鴉功能。分享給大家供大家參考，具體如下：

下面仿一個(gè)Android手寫板和涂鴉的功能，直接上代碼：

write_pad.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:greendroid="http://schemas.android.com/apk/res/com.cyrilmottier.android.gdcatalog"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:orientation="vertical" >
  <FrameLayout
    android:id="@+id/tablet_view"
    android:layout_width="fill_parent"
    android:layout_height="300dp" >
  </FrameLayout>
  <LinearLayout
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:background="@android:drawable/bottom_bar"
    android:paddingTop="4dp" >
    <Button
      android:id="@+id/write_pad_ok"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:text="確定" />
    <Button
      android:id="@+id/write_pad_clear"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:text="清除" />
    <Button
      android:id="@+id/write_pad_cancel"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:text="取消" />
  </LinearLayout>
</LinearLayout>

這個(gè)是手寫板的主要布局文件，能夠手寫的部分是一個(gè)FrameLayout。下面有確定、清除和取消按鈕，用來保存和擦除簽名。

主要代碼邏輯如下：

MainActivity.java

package com.jackie.handwriting;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import android.app.Activity;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageView;
import android.widget.TextView;
public class MainActivity extends Activity {
  private ImageView mIVSign;
  private TextView mTVSign;
  private Bitmap mSignBitmap;
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mIVSign = (ImageView) findViewById(R.id.iv_sign);
    mTVSign = (TextView) findViewById(R.id.tv_sign);
    mTVSign.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View view) {
        WritePadDialog mWritePadDialog = new WritePadDialog(
            MainActivity.this, new WriteDialogListener() {
              @Override
              public void onPaintDone(Object object) {
                mSignBitmap = (Bitmap) object;
                createSignFile();
                mIVSign.setImageBitmap(mSignBitmap);
                mTVSign.setVisibility(View.GONE);
              }
            });
        mWritePadDialog.show();
      }
    });
  }
  //創(chuàng)建簽名文件
  private void createSignFile() {
    ByteArrayOutputStream baos = null;
    FileOutputStream fos = null;
    String path = null;
    File file = null;
    try {
      path = Environment.getExternalStorageDirectory() + File.separator + System.currentTimeMillis() + ".jpg";
      file = new File(path);
      fos = new FileOutputStream(file);
      baos = new ByteArrayOutputStream();
      //如果設(shè)置成Bitmap.compress(CompressFormat.JPEG, 100, fos) 圖片的背景都是黑色的
      mSignBitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
      byte[] b = baos.toByteArray();
      if (b != null) {
        fos.write(b);
      }
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      try {
        if (fos != null) {
          fos.close();
        }
        if (baos != null) {
          baos.close();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }
}

PaintView.java

package com.jackie.handwriting;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PorterDuff;
import android.view.MotionEvent;
import android.view.View;
public class PaintView extends View {
  private Paint mPaint;
  private Path mPath;
  private Bitmap mBitmap;
  private Canvas mCanvas;
  private int screenWidth, screenHeight;
  private float currentX, currentY;
  public PaintView(Context context, int screenWidth, int screenHeight) {
    super(context);
    this.screenWidth = screenWidth;
    this.screenHeight = screenHeight;
    init();
  }
  private void init() {
    mPaint = new Paint();
    mPaint.setAntiAlias(true); // 去除鋸齒
    mPaint.setStrokeWidth(5);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setColor(Color.BLACK);
    mPath = new Path();
    mBitmap = Bitmap.createBitmap(screenWidth, screenHeight, Config.ARGB_8888);
    mCanvas = new Canvas(mBitmap);
//   mCanvas.drawColor(Color.WHITE);
  }
  @Override
  protected void onDraw(Canvas canvas) {
    canvas.drawBitmap(mBitmap, 0, 0, null);
    canvas.drawPath(mPath, mPaint);
  }
  @Override
  public boolean onTouchEvent(MotionEvent event) {
    float x = event.getX();
    float y = event.getY();
    switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:
      currentX = x;
      currentY = y;
      mPath.moveTo(currentX, currentY);
      break;
    case MotionEvent.ACTION_MOVE:
      currentX = x;
      currentY = y;
      mPath.quadTo(currentX, currentY, x, y); // 畫線
      break;
    case MotionEvent.ACTION_UP:
      mCanvas.drawPath(mPath, mPaint);
      break;
    }
    invalidate();
    return true;
  }
  public Bitmap getPaintBitmap() {
    return resizeImage(mBitmap, 320, 480);
  }
  public Path getPath() {
    return mPath;
  }
  // 縮放
  public static Bitmap resizeImage(Bitmap bitmap, int width, int height) {
    int originWidth = bitmap.getWidth();
    int originHeight = bitmap.getHeight();
    float scaleWidth = ((float) width) / originWidth;
    float scaleHeight = ((float) height) / originHeight;
    Matrix matrix = new Matrix();
    matrix.postScale(scaleWidth, scaleHeight);
    Bitmap resizedBitmap = Bitmap.createBitmap(bitmap, 0, 0, originWidth,
        originHeight, matrix, true);
    return resizedBitmap;
  }
  //清除畫板
  public void clear() {
    if (mCanvas != null) {
      mPath.reset();
      mCanvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
      invalidate();
    }
  }
}

WritePadDialog.java

package com.jackie.handwriting;
import android.app.Dialog;
import android.content.Context;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.Toast;
public class WritePadDialog extends Dialog {
  private Context mContext;
  private WriteDialogListener mWriteDialogListener;
  private PaintView mPaintView;
  private FrameLayout mFrameLayout;
  private Button mBtnOK, mBtnClear, mBtnCancel;
  public WritePadDialog(Context context,
      WriteDialogListener writeDialogListener) {
    super(context);
    this.mContext = context;
    this.mWriteDialogListener = writeDialogListener;
  }
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE); //無標(biāo)題
    setContentView(R.layout.write_pad);
    mFrameLayout = (FrameLayout) findViewById(R.id.tablet_view);
    // 獲取屏幕尺寸
    DisplayMetrics mDisplayMetrics = new DisplayMetrics();
    getWindow().getWindowManager().getDefaultDisplay().getMetrics(mDisplayMetrics);
    int screenWidth = mDisplayMetrics.widthPixels;
    int screenHeight = mDisplayMetrics.heightPixels;
    mPaintView = new PaintView(mContext, screenWidth, screenHeight);
    mFrameLayout.addView(mPaintView);
    mPaintView.requestFocus();
    mBtnOK = (Button) findViewById(R.id.write_pad_ok);
    mBtnOK.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        if (mPaintView.getPath().isEmpty()) {
          Toast.makeText(mContext, "請(qǐng)寫下你的大名", Toast.LENGTH_SHORT).show();
          return;
        }
        mWriteDialogListener.onPaintDone(mPaintView.getPaintBitmap());
        dismiss();
      }
    });
    mBtnClear = (Button) findViewById(R.id.write_pad_clear);
    mBtnClear.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        mPaintView.clear();
      }
    });
    mBtnCancel = (Button) findViewById(R.id.write_pad_cancel);
    mBtnCancel.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        cancel();
      }
    });
  }
}

WriteDilogListener.java

package com.jackie.handwriting;
/**
 * 監(jiān)聽手寫板對(duì)話框
 * @author chengcj1
 *
 */
public interface WriteDialogListener {
  public void onPaintDone(Object object);
}

效果如下：