开发应用程序以拍摄照片并在其上绘制GPS坐标。 刚刚对drawtext（）方法进行了测试，该方法没有显示出来。 GPS工作正常。 相机工作正常。 画布有问题。
mainactivity.java的代码
package com.example.camera;
import android.os.Bundle;
import android.app.Activity;
import android.widget.ImageView;
import android.widget.Button;
import android.view.View;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.net.Uri;
import android.content.Context;
import android.content.Intent;
import android.content.res.Resources;
import android.provider.MediaStore;
import java.io.File;
import java.io.FileOutputStream;
import android.os.Environment;
import android.util.Log;
import java.text.SimpleDateFormat;
import java.util.Locale;
import java.util.Date;
import android.widget.Toast;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
public class MainActivity extends Activity
{
double lat,lon;
private static final String TAG = "CallCamera";
private static final int CAPTURE_IMAGE_ACTIVITY_REQ = 0;
private String photoUri=null;
Uri fileUri = null;
ImageView photoImage = null;
private File getOutputPhotoFile()
{
File directory = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), getPackageName());
Log.d("directory check ", directory.toString());
if (!directory.exists())
{
if (!directory.mkdirs())
{
Log.e(TAG, "Failed to create storage directory.");
return null;
}
}
String timeStamp = new SimpleDateFormat("yyyMMdd_HHmmss", Locale.US).format(new Date());
return new File(directory.getPath() + File.separator + "IMG_"
+ timeStamp + ".jpg");
}
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
photoImage = (ImageView) findViewById(R.id.photo_image);
try
{
LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
LocationListener ll = new mylocationlistener();
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, ll);
}
catch(Exception e)
{
Log.d("GPS","Exception in location part-->"+e.toString());
}
Button callCameraButton = (Button)
findViewById(R.id.button_callcamera);
callCameraButton.setOnClickListener( new View.OnClickListener() {
public void onClick(View view) {
Intent i = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
fileUri = Uri.fromFile(getOutputPhotoFile());
i.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
startActivityForResult(i, CAPTURE_IMAGE_ACTIVITY_REQ );
}
}
);
}
private class mylocationlistener implements LocationListener
{
@Override
public void onLocationChanged(Location location)
{
if (location != null)
{
Log.d("LOCATION CHANGED", location.getLatitude() + "");
Log.d("LOCATION CHANGED", location.getLongitude() + "");
lat=location.getLatitude();
lon=location.getLongitude();
}
}
@Override
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String arg0)
{
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
// TODO Auto-generated method stub
}
}
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == CAPTURE_IMAGE_ACTIVITY_REQ)
{
if (resultCode == RESULT_OK)
{
Uri photoUri = null;
if (data == null)
{
// A known bug here! The image should have saved in fileUri
Log.d("Image Code","Image Saved");
photoUri = fileUri;
}
else
{
photoUri = data.getData();
Log.d("Image Code","Image Saved at"+data.getData());
}
drawLatLong(photoUri.getPath());
}
else if (resultCode == RESULT_CANCELED)
{
Log.d("Image Code", "Cancled");
}
else
{
Log.d("Image Code", "Callout for image capture failed!");
}
}
}
/**
* takes the PhotoURI and draws the Latitude and longitude over it
* @param photoUri
*/
private void drawLatLong(String photoUri)
{
File imageFile = new File (photoUri);
if (imageFile.exists())
{
Bitmap bitmap = BitmapFactory.decodeFile(imageFile.getAbsolutePath());
// Resources res=getResources();
// BitmapDrawable drawable = new BitmapDrawable(res,bitmap);
try
{
Canvas canvas = new Canvas(bitmap);
Paint paint = new Paint();
paint.setColor(Color.WHITE); // Text Color
paint.setStrokeWidth(12); // Text Size
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER)); // Text Overlapping Pattern
// some more settings...
canvas.drawBitmap(bitmap, 0, 0, paint);
canvas.drawText("Testing...", 10, 10, paint);
-
FileOutputStream fOut = new FileOutputStream(photoUri);
Log.d("Path"," "+photoUri);
bitmap.compress(Bitmap.CompressFormat.JPEG, 85, fOut);
fOut.flush();
fOut.close();
System.out.println(photoUri);
//bitmap.recycle();
// System.gc();
}
catch(Exception ex)
{
Log.d("Canvas Part", "Exception caused in canvas drawing-->"+ex.toString());
}
showPhoto(bitmap);
}
}
/**
* Takes the Bitmap from the drawLatLong() method and displays it over the image view.
* @param bitmapShow
*/
private void showPhoto(Bitmap bitmapShow)
{
try
{
Resources res=getResources();
BitmapDrawable drawable = new BitmapDrawable(res,bitmapShow);
photoImage.setImageDrawable(drawable);
photoImage.setScaleType(ImageView.ScaleType.FIT_CENTER);
photoImage.setImageBitmap(bitmapShow);
}
catch(Exception ex)
{
Log.d("canvas","exception in canvas"+ex);
}
}
}
清单文件
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.camera"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.CAMERA"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"></uses-permission>
<uses-permission
android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-feature android:name="android.hardware.camera" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.camera.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
答案 0 :(得分：0)
位图需要是inMutable。使用以下代码设置它。
BitmapFactory.Options options = new BitmapFactory.Options();
options.inMutable = true;
Bitmap bitmap = BitmapFactory.decodeFile(imageFile.getAbsolutePath(),options);
由于画布已经具有此位图，因此不需要此部分代码。
//Not needed:
//canvas.drawBitmap(bitmap, 0, 0, paint);