Android中Intent跳转的那些事儿

在android中，运用Intent跳转页面时，常用的是利用Bundle携带数据跳转到另外一个activity，其实携带图片跳转的原理也和携带数据跳转一样，首先将图片转化成bitmap，再将bitmap转化成byte数组，也就是说，根本的原理是与数据传送一样。下面是本人写的一个简单的demo，可以给大家参考参考。
在数据发送到第二个activity的时候我们还可以对图片做裁剪处理，我在下面也为大家剪贴了出来。

public class MainActivity extends AppCompatActivity {
private ImageView image;
private String path =    "http://192.168.1.120/18363677172/userphoto/18363677172.png";

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

//严苛模式，在主线程中请求网络，不建议使用，建议新开子线程访问网络
StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
.detectDiskReads().detectDiskWrites().detectNetwork()
.penaltyLog().build());
StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()
.detectLeakedSqlLiteObjects().detectLeakedClosableObjects()
.penaltyLog().penaltyDeath().build());

image = (ImageView) findViewById(R.id.imageview);

//        new Thread() {
//            @Override
//            public void run() {
try {
image.setImageBitmap(getBitmap(path));
image.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MainActivity.this, "我要跳了啊", Toast.LENGTH_SHORT).show();
byte buff[] = new byte[0];//看你图有多大..自己看着改
try {
buff = Bitmap2Bytes(getBitmap(path));//这里的LZbitmap是Bitmap类的,跟第一个方法不同
} catch (IOException e) {
e.printStackTrace();
}
Intent myIntent = new Intent(MainActivity.this,Open.class);
myIntent.putExtra("bitmap",buff);
startActivity(myIntent);
finish();
}
});

} catch (Exception e) {
e.printStackTrace();
}
//            }
//        }.start();

}

public static Bitmap getBitmap(String path) throws IOException {

bca0
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5000);
conn.setRequestMethod("GET");
if (conn.getResponseCode() == 200) {
InputStream inputStream = conn.getInputStream();
Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
return bitmap;
}
return null;
}
private byte[] Bitmap2Bytes(Bitmap bm){
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.JPEG, 100, baos);
return baos.toByteArray();
}
}

public class Open extends Activity {
private ImageView imageView;
private TextView textView;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.open);

StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
.detectDiskReads().detectDiskWrites().detectNetwork()
.penaltyLog().build());
StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()
.detectLeakedSqlLiteObjects().detectLeakedClosableObjects()
.penaltyLog().penaltyDeath().build());

imageView= (ImageView) findViewById(R.id.image);
textView= (TextView) findViewById(R.id.tv);

Intent myIntent = getIntent();
byte buff[] = (byte[]) myIntent.getSerializableExtra("bitmap");

Bitmap bitmap = BitmapFactory.decodeByteArray(buff, 0, buff.length); // 生成位图

imageView.setImageBitmap(toRoundCorner(bitmap,2)); // 显示位图

//        Bitmap bmp= BitmapFactory.decodeByteArray(buff, 0, buff.length);//重新编码出Bitmap对象
////        Drawable drawable =new BitmapDrawable(bmp);
//        imageView.setImageBitmap(bmp);
Toast.makeText(Open.this, "byte"+buff, Toast.LENGTH_SHORT).show();
}

public static Bitmap toRoundCorner(Bitmap bitmap, float ratio) {
System.out.println("图片是否变成圆形模式了+++++++++++++");
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(output);

final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);

paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
canvas.drawRoundRect(rectF, bitmap.getWidth() / ratio,
bitmap.getHeight() / ratio, paint);

paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
System.out.println("pixels+++++++" + String.valueOf(ratio));

return output;

}

}