AnimationView.java
package com.example.androidanimationalongpath;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PathMeasure;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
public class AnimationView extends View {
Paint paint;
Bitmap bm;
int bm_offsetX, bm_offsetY;
Path animPath;
PathMeasure pathMeasure;
float pathLength;
float step; //distance each step
float distance; //distance moved
float curX, curY;
float curAngle; //current angle
float targetAngle; //target angle
float stepAngle; //angle each step
float[] pos;
float[] tan;
Matrix matrix;
Path touchPath;
static int FORWARD = 1;
static int BACKWARD = -1;
int direction;
public AnimationView(Context context) {
super(context);
initMyView();
}
public AnimationView(Context context, AttributeSet attrs) {
super(context, attrs);
initMyView();
}
public AnimationView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
initMyView();
}
public void initMyView(){
paint = new Paint();
paint.setColor(Color.BLUE);
paint.setStrokeWidth(1);
paint.setStyle(Paint.Style.STROKE);
bm = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
bm_offsetX = bm.getWidth()/2;
bm_offsetY = bm.getHeight()/2;
animPath = new Path();
pos = new float[2];
tan = new float[2];
matrix = new Matrix();
touchPath = new Path();
step = 1; //default
stepAngle = 1; //default
direction = FORWARD; //default
}
@Override
protected void onDraw(Canvas canvas) {
if(animPath.isEmpty()){
return;
}
canvas.drawPath(animPath, paint);
matrix.reset();
if((targetAngle-curAngle)>stepAngle){
curAngle += stepAngle;
matrix.postRotate(curAngle, bm_offsetX, bm_offsetY);
matrix.postTranslate(curX, curY);
canvas.drawBitmap(bm, matrix, null);
invalidate();
}else if((curAngle-targetAngle)>stepAngle){
curAngle -= stepAngle;
matrix.postRotate(curAngle, bm_offsetX, bm_offsetY);
matrix.postTranslate(curX, curY);
canvas.drawBitmap(bm, matrix, null);
invalidate();
}else{
curAngle=targetAngle;
if((direction==FORWARD && distance < pathLength)
||(direction==BACKWARD && distance > 0)){
pathMeasure.getPosTan(distance, pos, tan);
targetAngle = (float)(Math.atan2(tan[1], tan[0])*180.0/Math.PI);
matrix.postRotate(curAngle, bm_offsetX, bm_offsetY);
curX = pos[0]-bm_offsetX;
curY = pos[1]-bm_offsetY;
matrix.postTranslate(curX, curY);
canvas.drawBitmap(bm, matrix, null);
distance += step * direction;
invalidate();
}else{
matrix.postRotate(curAngle, bm_offsetX, bm_offsetY);
matrix.postTranslate(curX, curY);
canvas.drawBitmap(bm, matrix, null);
}
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
int action = event.getAction();
switch(action){
case MotionEvent.ACTION_DOWN:
touchPath.reset();
touchPath.moveTo(event.getX(), event.getY());
break;
case MotionEvent.ACTION_MOVE:
touchPath.lineTo(event.getX(), event.getY());
break;
case MotionEvent.ACTION_UP:
touchPath.lineTo(event.getX(), event.getY());
animPath = new Path(touchPath);
pathMeasure = new PathMeasure(animPath, false);
pathLength = pathMeasure.getLength();
//step = 1;
distance = 0;
curX = 0;
curY = 0;
//stepAngle = 1;
curAngle = 0;
targetAngle = 0;
direction = FORWARD;
invalidate();
break;
}
return true;
}
public void setSpeed(int sp){
step = sp;
stepAngle = sp;
}
public void replayForward(){
direction = FORWARD;
invalidate();
}
public void replayBackward(){
direction = BACKWARD;
invalidate();
}
}
/res/layout/activity_main.xml
<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"
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="com.example.androidanimationalongpath.MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:autoLink="web"
android:text="http://android-er.blogspot.com/"
android:textStyle="bold" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<Button
android:id="@+id/replayfor"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="match_parent"
android:text="Replay/Forward" />
<Button
android:id="@+id/replayback"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="match_parent"
android:text="Replay/Backward" />
</LinearLayout>
<SeekBar
android:id="@+id/speedbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:max="10"
android:progress="1"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<com.example.androidanimationalongpath.AnimationView
android:id="@+id/animationview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="10dp"
android:background="@android:color/darker_gray" />
</LinearLayout>
</LinearLayout>
MainActivity.java
package com.example.androidanimationalongpath;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import android.os.Bundle;
public class MainActivity extends ActionBarActivity {
AnimationView animationView;
SeekBar speedBar;
Button btnForward, btnbackward;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
animationView = (AnimationView)findViewById(R.id.animationview);
speedBar = (SeekBar)findViewById(R.id.speedbar);
speedBar.setOnSeekBarChangeListener(speedBarOnSeekBarChangeListener);
animationView.setSpeed(speedBar.getProgress()); //set default speed
btnForward = (Button)findViewById(R.id.replayfor);
btnForward.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
animationView.replayForward();
}});
btnbackward = (Button)findViewById(R.id.replayback);
btnbackward.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
animationView.replayBackward();
}});
}
OnSeekBarChangeListener speedBarOnSeekBarChangeListener =
new OnSeekBarChangeListener(){
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
//offset from SeekBar 0~19 to step 1~10
animationView.setSpeed(progress);
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {}
@Override
public void onStopTrackingTouch(SeekBar seekBar) {}
};
}
Download the files.More example of Drawing Path on canvas of custom View.
