5.Android硬件访问服务使用反射

1>. 采用反射机制的方式去访问硬件

1<. 优化安装包大小

步骤：

1<. File -> Project Structure -> Modules ->

2<. app -> Dependencies -> Scope -> Provided

2<. 开始使用反射机制的改写

1<. 开始代码转换

**[!原来的]**
iLedService = ILedService.Stub.asInterface(ServiceManager.getService("leds"));

**[!现在的]**
Method getService = Class.forName("android.os.ServiceManager").getMethod("getService", String.class);
Object ledService = getService.invoke(null, "leds");
Method asInterface = Class.forName("android.os.ILedService$Stub").getMethod("asInterface", IBinder.class);
Proxy   = asInterface.invoke(null, ledService);
ledCtrl = Class.forName("android.os.ILedService$Stub$Proxy").getMethod("ledCtrl", int.class, int.class);

2<. 使用：

ledCtrl.invoke(Proxy, 0, 0);

示例代码

1<. MainActivity.java –APP层

package com.becauseican.app_0001_leddemo;

import android.app.Activity;
import android.os.Bundle;
import android.os.IBinder;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.Toast;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

//import android.os.ILedService;

public class MainActivity extends Activity {
private Button buttonLead = null;
private boolean boolLead = false;
private CheckBox checkBoxLed1 = null;
private CheckBox checkBoxLed2 = null;
private CheckBox checkBoxLed3 = null;
private CheckBox checkBoxLed4 = null;
//private ILedService iLedService = null;

Object Proxy = null;
Method ledCtrl = null;

/* 自己定义的类 */
class MyButtonListener implements View.OnClickListener {
@Override
public void onClick(View v) {

boolLead = !boolLead;
if (boolLead) {
buttonLead.setText("Close All");
checkBoxLed1.setChecked(true);
checkBoxLed2.setChecked(true);
checkBoxLed3.setChecked(true);
checkBoxLed4.setChecked(true);

/* 全部点亮 */
for (int i = 0; i < 4; ++i) {
try {
ledCtrl.invoke(Proxy, i, 1);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}

}

}else {
buttonLead.setText("Open All");
checkBoxLed1.setChecked(false);
checkBoxLed2.setChecked(false);
checkBoxLed3.setChecked(false);
checkBoxLed4.setChecked(false);

/* 全部熄灭 */
for (int i = 0; i < 4; ++i) {
try {
ledCtrl.invoke(Proxy, i, 0);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}

}
}
}
}

public void onCheckboxClicked(View view) {
// Is the view now checked?
boolean checked = ((CheckBox) view).isChecked();

// Check which checkbox was clicked
try {
switch(view.getId()) {
case R.id.CheckBoxLed4:
if (checked) {
Toast.makeText(getApplicationContext(), "CheckBoxLed4 on", Toast.LENGTH_SHORT).show();
ledCtrl.invoke(Proxy, 3, 1);
}
// Put some meat on the sandwich
else {
Toast.makeText(getApplicationContext(), "CheckBoxLed4 off", Toast.LENGTH_SHORT).show();
ledCtrl.invoke(Proxy, 3, 0);
}
// Remove the meat
break;
case R.id.CheckBoxLed3:
if (checked) {
Toast.makeText(getApplicationContext(), "CheckBoxLed3 on", Toast.LENGTH_SHORT).show();
ledCtrl.invoke(Proxy, 2, 1);
}
// Cheese me
else {
Toast.makeText(getApplicationContext(), "CheckBoxLed3 off", Toast.LENGTH_SHORT).show();
ledCtrl.invoke(Proxy, 2, 0);
}
// I'm lactose intolerant
break;
case R.id.CheckBoxLed2:
if (checked) {
Toast.makeText(getApplicationContext(), "CheckBoxLed2 on", Toast.LENGTH_SHORT).show();
ledCtrl.invoke(Proxy, 1, 1);
}
// Put some meat on the sandwich
else {
Toast.makeText(getApplicationContext(), "CheckBoxLed2 off", Toast.LENGTH_SHORT).show();
ledCtrl.invoke(Proxy, 1, 0);
}
// Remove the meat
break;
case R.id.CheckBoxLed1:
if (checked) {
Toast.makeText(getApplicationContext(), "CheckBoxLed1 on", Toast.LENGTH_SHORT).show();
ledCtrl.invoke(Proxy, 0, 1);
}
// Put some meat on the sandwich
else {
Toast.makeText(getApplicationContext(), "CheckBoxLed1 off", Toast.LENGTH_SHORT).show();
ledCtrl.invoke(Proxy, 0, 0);
}
// Remove the meat
break;
// TODO: Veggie sandwich
}
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}

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

buttonLead = (Button) findViewById(R.id.ButtonLead);

/* 获得硬件访问服务的实例化对象 */
/* 利用反射机制实现硬件访问服务
* iLedService = ILedService.Stub.asInterface(ServiceManager.getService("leds"));
*/

try {
Method getService = Class.forName("android.os.ServiceManager").getMethod("getService", String.class);
IBinder ledService = (IBinder) getService.invoke(null, "leds");
Method asInterface = Class.forName("android.os.ILedService$Stub").getMethod("asInterface", IBinder.class);
Proxy   = asInterface.invoke(null, ledService);
ledCtrl = Class.forName("android.os.ILedService$Stub$Proxy").getMethod("ledCtrl", int.class, int.class);
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}

checkBoxLed1 = (CheckBox) findViewById(R.id.CheckBoxLed1);
checkBoxLed2 = (CheckBox) findViewById(R.id.CheckBoxLed2);
checkBoxLed3 = (CheckBox) findViewById(R.id.CheckBoxLed3);
checkBoxLed4 = (CheckBox) findViewById(R.id.CheckBoxLed4);

/*      // 采用匿名类的方式
buttonLead.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v){
boolLead = !boolLead;
if (boolLead) {
buttonLead.setText("Close All");
}else {
buttonLead.setText("Open All");
}
}
});
*/
//使用自定义类的方式
buttonLead.setOnClickListener(new MyButtonListener());

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();

//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}

return super.onOptionsItemSelected(item);
}

@Override
protected void onDestroy() {
for (int i = 0; i < 4; ++i) {
try {
ledCtrl.invoke(Proxy, i, 0);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
super.onDestroy();
}
}