Android检测网络是否可用

public class Main extends Activity {

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

    public void click(View view) {
        
        if(isConn()){
            Toast.makeText(this, "网络可用", 0).show();
        }else{
            Toast.makeText(this, "网络不可用", 0).show();
            setNetworkMethod();
        }
        

    }

    private boolean isConn() {
        boolean flag = false;
        ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo network = cm.getActiveNetworkInfo();
        if (network != null) {
            flag = network.isAvailable();
        }
        return flag;
    }
    
    private void setNetworkMethod(){
        
        AlertDialog.Builder builder = new Builder(this);
        builder.setTitle("网络设置提示");
        builder.setMessage("网络连接不可用,是否进行设置?");
        builder.setPositiveButton("设置", new DialogInterface.OnClickListener(){

            @Override
            public void onClick(DialogInterface dialog, int which) {
                Intent intent = null;
                //判断手机系统的版本  即API大于10 就是3.0或以上版本 
                if(android.os.Build.VERSION.SDK_INT>10){
                    intent = new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS);
                }else{
                    intent = new Intent();
                    intent.setClassName("com.android.settings","com.android.settings.WirelessSettings");
                }
                startActivity(intent);                
            }
            
        }).setNegativeButton("取消", new DialogInterface.OnClickListener() {
            
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
            }
        });
        builder.show();
        
        
        
    }
    
    

}

需要添加一个权限:android.permission.ACCESS_NETWORK_STATE