工作之余,自己想着利用空闲时间做一些小工具出来,今天分享的是一个简单的画板工具,支持轨迹绘制、更换笔迹颜色等功能,并且可以把成品保存到系统相册。支持Android 13
先看一下效果,吐槽一下csdn的视频上传,质量压缩的比较厉害,然后比例也发生变化了,反正是大家凑合看吧,文末会放源码(我的所有demo的源码都是不需要积分的)
Android画板小工具测试视频
我主要放一下关键代码吧
1.自定义画板SignatureView
public class SignatureView extends View {private Context context;private Paint paint;private Bitmap bitmap;private Canvas canvas;private Path path;public SignatureView(Context context, AttributeSet attrs) {super(context, attrs);this.context = context;paint = new Paint();paint.setColor(Color.BLACK);paint.setStrokeWidth(10);paint.setStyle(Paint.Style.STROKE);// 获取屏幕尺寸DisplayMetrics displayMetrics = getResources().getDisplayMetrics();int screenWidth = displayMetrics.widthPixels;int screenHeight = displayMetrics.heightPixels;bitmap = Bitmap.createBitmap(screenWidth, screenHeight, Bitmap.Config.ARGB_8888);canvas = new Canvas(bitmap);canvas.drawColor(Color.WHITE);path = new Path();}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);canvas.drawBitmap(bitmap, 0, 0, paint);}@Overridepublic boolean onTouchEvent(MotionEvent event) {float x = event.getX();float y = event.getY();switch (event.getAction()) {case MotionEvent.ACTION_DOWN:path.reset();path.moveTo(x, y);break;case MotionEvent.ACTION_MOVE:path.lineTo(x, y);canvas.drawPath(path, paint);break;case MotionEvent.ACTION_UP:break;default:return false;}invalidate();return true;}public void setColor(int newColor) {paint.setColor(newColor);}public void clear() {canvas.drawColor(Color.WHITE);invalidate();}public Bitmap getSignatureBitmap() {return bitmap;}public int dpToPx(float dp) {float density = context.getResources().getDisplayMetrics().density;return Math.round(dp * density);}}
2.布局文件
<?xml version="1.0" encoding="utf-8"?>
<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"><com.swy.signdemo.SignatureViewandroid:id="@+id/signatureView"android:layout_width="match_parent"android:layout_height="0dp"android:layout_weight="1"android:background="#ffffff" /><Viewandroid:layout_width="match_parent"android:layout_height="1dp"android:background="#dcdcdc" /><LinearLayoutandroid:layout_width="wrap_content"android:layout_height="50dp"android:layout_gravity="bottom|end"android:layout_margin="10dp"android:orientation="horizontal"><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="当前颜色:" /><FrameLayoutandroid:layout_width="32dp"android:layout_height="32dp"android:layout_gravity="center_vertical"android:background="#000"><Viewandroid:id="@+id/view_color"android:layout_width="40dp"android:layout_height="40dp"android:layout_gravity="center"android:background="@color/black" /></FrameLayout><Buttonandroid:id="@+id/pickColor"android:layout_width="wrap_content"android:layout_height="match_parent"android:layout_marginLeft="20dp"android:text="更换颜色" /><Buttonandroid:id="@+id/clearButton"android:layout_width="wrap_content"android:layout_height="match_parent"android:layout_marginLeft="10dp"android:text="清空" /><Buttonandroid:id="@+id/saveButton"android:layout_width="wrap_content"android:layout_height="match_parent"android:layout_marginLeft="10dp"android:text="保存" /></LinearLayout></LinearLayout>
3.选择颜色的弹窗
public class PickColorWindow extends PopupWindow {private WindowPickColorBinding binding;private CommonAdapter<ColorData> commonAdapter;private List<ColorData> colors = new ArrayList<>();private ColorData colorDataSelected = null;public PickColorWindow(Activity context, ColorData color, PickColorCallBack callBack) {super(context);binding = WindowPickColorBinding.inflate(context.getLayoutInflater());setWidth(WindowManager.LayoutParams.MATCH_PARENT);setHeight(WindowManager.LayoutParams.MATCH_PARENT);setContentView(binding.getRoot());initColors();binding.viewColor.setBackgroundColor(Color.parseColor(color.getColorValue()));binding.btnCancel.setOnClickListener(v -> {dismiss();});binding.btnConfirm.setOnClickListener(v -> {callBack.onPick(colorDataSelected);dismiss();});binding.recycler.setLayoutManager(new GridLayoutManager(context, 4));commonAdapter = new CommonAdapter<ColorData>(context,R.layout.item_color, colors) {@Overridepublic void convert(CommonViewHolder holder, ColorData bean, int position) {holder.setBackgroundColor(R.id.view_color, Color.parseColor(bean.getColorValue()));holder.setOnClickListener(R.id.view_color, v -> {colorDataSelected = bean;binding.viewColor.setBackgroundColor(Color.parseColor(colorDataSelected.getColorValue()));});}@Overridepublic void footConvert(CommonViewHolder holder, int size) {}};binding.recycler.setAdapter(commonAdapter);}private void initColors() {colors.clear();colors.add(new ColorData("#000000"));colors.add(new ColorData("#e6194B"));colors.add(new ColorData("#3cb44b"));colors.add(new ColorData("#ffe119"));colors.add(new ColorData("#4363d8"));colors.add(new ColorData("#f58231"));colors.add(new ColorData("#42d4f4"));colors.add(new ColorData("#f032e6"));colors.add(new ColorData("#fabed4"));colors.add(new ColorData("#469990"));colors.add(new ColorData("#dcbeff"));colors.add(new ColorData("#9A6324"));colors.add(new ColorData("#fffac8"));colors.add(new ColorData("#800000"));colors.add(new ColorData("#aaffc3"));colors.add(new ColorData("#a9a9a9"));}public interface PickColorCallBack {void onPick(ColorData colorData);}
}
4.主界面
public class MainActivity extends AppCompatActivity {private ActivityMainBinding binding;private AlertDialog dialog;private static final int REQUEST_EXTERNAL_STORAGE = 1;private static String[] PERMISSIONS_STORAGE = {Manifest.permission.READ_EXTERNAL_STORAGE,Manifest.permission.WRITE_EXTERNAL_STORAGE};private boolean havePermission = false;private PickColorWindow pickColorWindow;private ColorData currentColor = new ColorData("#000000");@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);binding = ActivityMainBinding.inflate(getLayoutInflater());Window window = getWindow();window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);window.setStatusBarColor(Color.TRANSPARENT); // 设置状态栏颜色为透明window.getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);setContentView(binding.getRoot());binding.pickColor.setOnClickListener(v -> {showColorPickerDialog();});binding.clearButton.setOnClickListener(v -> {binding.signatureView.clear();});binding.saveButton.setOnClickListener(v -> {if (havePermission) {saveBitmap(binding.signatureView.getSignatureBitmap());} else {checkPermission();}});}private void saveBitmap(Bitmap bitmap) {// 获取外部存储目录String folderName = Environment.DIRECTORY_PICTURES;File file = new File(Environment.getExternalStoragePublicDirectory(folderName), "signature.png");try {if (file.exists()) {file.delete();}// 创建目录(如果不存在)file.getParentFile().mkdirs();// 尝试创建文件if (file.createNewFile()) {OutputStream os = new FileOutputStream(file);bitmap.compress(Bitmap.CompressFormat.PNG, 100, os); // 保存为PNG格式os.close();// 发送广播通知相册刷新sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(file)));Toast.makeText(MainActivity.this, "保存成功", Toast.LENGTH_SHORT).show();}} catch (IOException e) {e.printStackTrace();}}private void showColorPickerDialog() {if (pickColorWindow != null) {pickColorWindow.dismiss();pickColorWindow = null;}pickColorWindow = new PickColorWindow(this, currentColor, (ColorData color) -> {currentColor = color;binding.signatureView.setColor(Color.parseColor(currentColor.getColorValue()));binding.viewColor.setBackgroundColor(Color.parseColor(currentColor.getColorValue()));});pickColorWindow.showAsDropDown(binding.getRoot());}private void checkPermission() {//检查权限(NEED_PERMISSION)是否被授权 PackageManager.PERMISSION_GRANTED表示同意授权if (Build.VERSION.SDK_INT >= 30) {if (!Environment.isExternalStorageManager()) {if (dialog != null) {dialog.dismiss();dialog = null;}dialog = new AlertDialog.Builder(this).setTitle("提示")//设置标题.setMessage("请开启文件访问权限,否则无法正常使用本应用!").setNegativeButton("取消", (dialog, i) -> dialog.dismiss()).setPositiveButton("确定", (dialog, which) -> {dialog.dismiss();Intent intent = new Intent(Settings.ACTION_MANAGE_ALL_FILES_ACCESS_PERMISSION);startActivity(intent);}).create();dialog.show();} else {havePermission = true;saveBitmap(binding.signatureView.getSignatureBitmap());Log.i("swyLog", "Android 11以上,当前已有权限");}} else {if (Build.VERSION.SDK_INT > Build.VERSION_CODES.M) {if (ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {//申请权限if (dialog != null) {dialog.dismiss();dialog = null;}dialog = new AlertDialog.Builder(this).setTitle("提示")//设置标题.setMessage("请开启文件访问权限,否则无法正常使用本应用!").setPositiveButton("确定", (dialog, which) -> {dialog.dismiss();ActivityCompat.requestPermissions(MainActivity.this, PERMISSIONS_STORAGE, REQUEST_EXTERNAL_STORAGE);}).create();dialog.show();} else {havePermission = true;saveBitmap(binding.signatureView.getSignatureBitmap());Log.i("swyLog", "Android 6.0以上,11以下,当前已有权限");}} else {havePermission = true;saveBitmap(binding.signatureView.getSignatureBitmap());Log.i("swyLog", "Android 6.0以下,已获取权限");}}}@Overridepublic void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {super.onRequestPermissionsResult(requestCode, permissions, grantResults);switch (requestCode) {case REQUEST_EXTERNAL_STORAGE: {if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {havePermission = true;saveBitmap(binding.signatureView.getSignatureBitmap());Toast.makeText(this, "授权成功!", Toast.LENGTH_SHORT).show();} else {havePermission = false;Toast.makeText(this, "授权被拒绝!", Toast.LENGTH_SHORT).show();}return;}}}}
这个demo的功能还是相对比较简单的,然后没有什么好讲的,只不过这个demo中有涉及到Android 的运行时权限申请,兼容Android13的,可以重点关注一下,其他的都是UI层的东西,基本上把代码复制过去,就可以用了,真的有什么问题了,评论区留言
demo源码