android之imgView插件的使用

package xidian.dy.com.chujia;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;

import com.loopj.android.image.SmartImageView;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button btn = (Button) findViewById(R.id.btn);
        if(btn != null)
            btn.setOnClickListener(new MyLister());
    }

    class MyLister implements View.OnClickListener{
        @Override
        public void onClick(View v) {
            String url = "http://192.168.0.109/dog.jpg";
            SmartImageView siv = (SmartImageView) findViewById(R.id.img);
            if(siv != null)
                siv.setImageUrl(url);
        }
    }
}

<?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="xidian.dy.com.chujia.MainActivity">

        <Button
           android:id="@+id/btn"
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:text="@string/delete"
           />
        <com.loopj.android.image.SmartImageView
            android:id="@+id/img"
            android:layout_width="100dp"
            android:layout_height="100dp"
            android:src="@drawable/dog1"
            />
</LinearLayout>