问题
I am developing an app that sends DTMF tones over an active call in android. I searched a lot to implement this feature in my app and i found this : com.android.internal.telecom.IInCallAdapter interface that extends android.os.IInterface. There is a method playDtmfTone(String s,Char c) inside IInCallAdapter that we can use to send DTMF tones over an active call. I have an activity HelloPage.java that do so, but getting java.lang.ClassCastException error while initializing an object of IInCallAdapter. Well i know what this error means but don't know how to deal with this. Here is my code :
public class HelloPage extends Activity implements View.OnClickListener{
Button DTMF_b1,DTMF_b2,DTMF_b3,DTMF_b4,DTMF_b5,DTMF_b6,DTMF_b7,DTMF_b8,DTMF_b9,DTMF_b0,DTMF_bS,DTMF_bP;
private TextView DTMFToneDialedView;
private String DTMFToneDialedNumber = "";
private String callId;
private IInCallAdapter mIInCallAdapter;
@Override
protected void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_hello_page);
mIInCallAdapter = (IInCallAdapter) this; /*I am getting error here in this line*/
DTMF_b1 = (Button) findViewById(R.id.id_playDTMF1);
DTMF_b2 = (Button) findViewById(R.id.id_playDTMF2);
DTMF_b3 = (Button) findViewById(R.id.id_playDTMF3);
DTMF_b4 = (Button) findViewById(R.id.id_playDTMF4);
DTMF_b5 = (Button) findViewById(R.id.id_playDTMF5);
DTMF_b6 = (Button) findViewById(R.id.id_playDTMF6);
DTMF_b7 = (Button) findViewById(R.id.id_playDTMF7);
DTMF_b8 = (Button) findViewById(R.id.id_playDTMF8);
DTMF_b9 = (Button) findViewById(R.id.id_playDTMF9);
DTMF_bS = (Button) findViewById(R.id.id_playDTMFStar);
DTMF_b0 = (Button) findViewById(R.id.id_playDTMF0);
DTMF_bP = (Button) findViewById(R.id.id_playDTMFPound);
callId = MainActivity.telecomCallId; //Getting telecom Call ID from a static variable in a MainActivity
DTMFToneDialedView = (TextView) findViewById(R.id.id_DTMFToneDialedKey);
DTMF_b1.setOnClickListener(this);
DTMF_b2.setOnClickListener(this);
DTMF_b3.setOnClickListener(this);
DTMF_b4.setOnClickListener(this);
DTMF_b5.setOnClickListener(this);
DTMF_b6.setOnClickListener(this);
DTMF_b7.setOnClickListener(this);
DTMF_b8.setOnClickListener(this);
DTMF_b9.setOnClickListener(this);
DTMF_bS.setOnClickListener(this);
DTMF_b0.setOnClickListener(this);
DTMF_bP.setOnClickListener(this);
}
//This method updated the screen what we dial
public void dialedNumberUpdater(String key){
DTMFToneDialedNumber = DTMFToneDialedNumber + key;
DTMFToneDialedView.setText(DTMFToneDialedNumber);
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.id_playDTMF1:
try {
mIInCallAdapter.playDtmfTone(callId, '1');
dialedNumberUpdater("1");
}catch (Exception e){
dialedNumberUpdater("w"); //updating 'w' into the screen so that user can see it is not working.
}
break;
case R.id.id_playDTMF2:
try {
mIInCallAdapter.playDtmfTone(callId, '2');
dialedNumberUpdater("2");
}catch (Exception e){
dialedNumberUpdater("w");
}
break;
case R.id.id_playDTMF3:
try {
mIInCallAdapter.playDtmfTone(callId, '3');
dialedNumberUpdater("3");
}catch (Exception e){
dialedNumberUpdater("w");
}
break;
case R.id.id_playDTMF4:
try {
mIInCallAdapter.playDtmfTone(callId, '4');
dialedNumberUpdater("4");
}catch (Exception e){
dialedNumberUpdater("w");
}
break;
case R.id.id_playDTMF5:
try {
mIInCallAdapter.playDtmfTone(callId, '5');
dialedNumberUpdater("5");
}catch (Exception e){
dialedNumberUpdater("w");
}
break;
case R.id.id_playDTMF6:
try {
mIInCallAdapter.playDtmfTone(callId, '6');
dialedNumberUpdater("6");
}catch (Exception e){
dialedNumberUpdater("w");
}
break;
case R.id.id_playDTMF7:
try {
mIInCallAdapter.playDtmfTone(callId, '7');
dialedNumberUpdater("7");
}catch (Exception e){
dialedNumberUpdater("w");
}
break;
case R.id.id_playDTMF8:
try {
mIInCallAdapter.playDtmfTone(callId, '8');
dialedNumberUpdater("8");
}catch (Exception e){
dialedNumberUpdater("w");
}
break;
case R.id.id_playDTMF9:
try {
mIInCallAdapter.playDtmfTone(callId, '9');
dialedNumberUpdater("9");
}catch (Exception e){
dialedNumberUpdater("w");
}
break;
case R.id.id_playDTMFStar:
try {
mIInCallAdapter.playDtmfTone(callId, '*');
dialedNumberUpdater("*");
}catch (Exception e){
dialedNumberUpdater("w");
}
break;
case R.id.id_playDTMF0:
try {
mIInCallAdapter.playDtmfTone(callId, '0');
dialedNumberUpdater("0");
}catch (Exception e){
dialedNumberUpdater("w");
}
break;
case R.id.id_playDTMFPound:
try {
mIInCallAdapter.playDtmfTone(callId, '#');
dialedNumberUpdater("#");
}catch (Exception e){
dialedNumberUpdater("w");
}
break;
}
}
}
Here is the Logcat :
01-29 01:43:07.649 565-1247/? I/ActivityManager﹕ START u0 {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=algor7.code.backgroundcallingapp/.HelloPage} from uid 10099 on display 0
01-29 01:43:07.794 13439-13439/algor7.code.backgroundcallingapp E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: algor7.code.backgroundcallingapp, PID: 13439
java.lang.RuntimeException: Unable to start activity ComponentInfo{algor7.code.backgroundcallingapp/algor7.code.backgroundcallingapp.HelloPage}: java.lang.ClassCastException: algor7.code.backgroundcallingapp.HelloPage cannot be cast to android.os.IInterface
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.ClassCastException: algor7.code.backgroundcallingapp.HelloPage cannot be cast to android.os.IInterface
at algor7.code.backgroundcallingapp.HelloPage.onCreate(HelloPage.java:39)
at android.app.Activity.performCreate(Activity.java:6251)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
01-29 01:43:07.813 565-876/? W/ActivityManager﹕ Force finishing activity algor7.code.backgroundcallingapp/.HelloPage
01-29 01:43:08.345 565-578/? W/ActivityManager﹕ Activity pause timeout for ActivityRecord{454bc33 u0 algor7.code.backgroundcallingapp/.HelloPage t191 f}
Please help me to solve this issue. Thank you in advance.
回答1:
Because your this is a HelloPage object. It is not an IInCallAdapter, does not inherit from it, and does not extend it. It can't be cast as one. Why would you think it could be?
回答2:
Create a class that implements IInCallAdapter and then implement all its methods
public class ClassName implements IInCallAdapter {
...
}
Then you can create an instance of this class in your Activity class
来源：https://stackoverflow.com/questions/35073211/getting-java-lang-classcastexception-while-sending-dtmf-tones-over-an-active-cal