Android_用于电子签名手势识别_例子_

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.gesture.builder;

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.MotionEvent;
import android.gesture.GestureOverlayView;
import android.gesture.Gesture;
import android.gesture.GestureLibrary;
import android.widget.TextView;
import android.widget.Toast;

import java.io.File;

public class CreateGestureActivity extends Activity {
  private static final float LENGTH_THRESHOLD = 120.0f;

  private Gesture mGesture;
  private View mDoneButton;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    
    setContentView(R.layout.create_gesture);

    mDoneButton = findViewById(R.id.done);

    GestureOverlayView overlay = (GestureOverlayView) findViewById(R.id.gestures_overlay);
    overlay.addOnGestureListener(new GesturesProcessor());
  }

  @Override
  protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    
    if (mGesture != null) {
      outState.putParcelable("gesture", mGesture);
    }
  }

  @Override
  protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    
    mGesture = savedInstanceState.getParcelable("gesture");
    if (mGesture != null) {
      final GestureOverlayView overlay =
          (GestureOverlayView) findViewById(R.id.gestures_overlay);
      overlay.post(new Runnable() {
        public void run() {
          overlay.setGesture(mGesture);
        }
      });

      mDoneButton.setEnabled(true);
    }
  }

  public void addGesture(View v) {
    if (mGesture != null) {
      final TextView input = (TextView) findViewById(R.id.gesture_name);
      final CharSequence name = input.getText();
      if (name.length() == 0) {
        input.setError(getString(R.string.error_missing_name));
        return;
      }

      final GestureLibrary store = GestureBuilderActivity.getStore();
      store.addGesture(name.toString(), mGesture);
      store.save();

      setResult(RESULT_OK);

      final String path = new File(Environment.getExternalStorageDirectory(),
          "gestures").getAbsolutePath();
      Toast.makeText(this, getString(R.string.save_success, path), Toast.LENGTH_LONG).show();
    } else {
      setResult(RESULT_CANCELED);
    }

    finish();
    
  }
  
  @SuppressWarnings({"UnusedDeclaration"})
  public void cancelGesture(View v) {
    setResult(RESULT_CANCELED);
    finish();
  }
  
  private class GesturesProcessor implements GestureOverlayView.OnGestureListener {
    public void onGestureStarted(GestureOverlayView overlay, MotionEvent event) {
      mDoneButton.setEnabled(false);
      mGesture = null;
    }

    public void onGesture(GestureOverlayView overlay, MotionEvent event) {
    }

    public void onGestureEnded(GestureOverlayView overlay, MotionEvent event) {
      mGesture = overlay.getGesture();
      if (mGesture.getLength() < LENGTH_THRESHOLD) {
        overlay.clear(false);
      }
      mDoneButton.setEnabled(true);
    }

    public void onGestureCancelled(GestureOverlayView overlay, MotionEvent event) {
    }
  }
}