我正在使用okhttp库处理POST API。一切都工作正常，除了我无法找到一种方法来显示一个简单的吐司消息成功回调。如何向用户调用toast消息，以便他知道在成功和失败回调中是否在服务器上发布了数据？
P.S下面的代码属于不属于活动类的不同类。
这是我的代码：
public DataSource(Context context) {
this.mContext = context;
mDbHelper = new DBHelper(mContext);
mDatabase = mDbHelper.getWritableDatabase();
}
post(URL, jsonData, new Callback() {
@Override
public void onFailure(Call call, IOException e) {
Log.i("FAILED", "onFailure: Failed to upload data to server");
//here I want to show toast message
}
@Override
public void onResponse(Call call, Response response) throws IOException {
if (response.isSuccessful()) {
Log.i("SUCCESSFUL", "onSuccess: data uploaded");
//here I want to show toast message
} else {
Log.i("UN SUCCESSFUL", "onFailure: Failed to upload data to server");
//here I want to show toast message
}
}
});
答案 0 :(得分：6)
每个应用都有自己的特殊线程来运行UI对象，例如View对象;这个线程称为UI线程。只有在UI线程上运行的对象才能访问该线程上的其他对象。由于您在线程池中的线程上运行的任务未在UI线程上运行，因此它们无权访问UI对象。要将数据从后台线程移动到UI线程，请使用在UI线程上运行的Handler，或者可以使用Android实现，如此处所示。
- 案例1
MyActivity.this.runOnUiThread(new Runnable() {
@Override
void run() {
Toast.makeText(MyActivity.this,
"message", Toast.LENGTH_LONG).show();
});
- 案例2
new Handler(Looper.getMainLooper()).post(new Runnable() {
@Override
public void run() {
Toast.makeText(MyActivity.this,
"message", Toast.LENGTH_LONG).show();
}
});
如果它是主线程你会直接使用它
Toast.makeText(MyActivity.this,
"message", Toast.LENGTH_LONG).show();
答案 1 :(得分：1)
此回调是一个异步函数，您可以在UI线程中更改View，这样Handler将为您提供帮助。
....
private final static int MSG_SUCCESS = 0x0001;
private final static int MSG_FAIL = 0x0002;
private Handler handler = new Handler(){
@Override
public void handleMessage(Message msg) {
switch(msg.what){
case MSG_SUCCESS:
//Toast success
break;
case MSG_FAIL:
//Toast fail
break;
default:
break;
}
}
};
......
......
if (response.isSuccessful()) {
Log.i("SUCCESSFUL", "onSuccess: data uploaded");
handler.sendEmptyMessage(MSG_SUCCESS);
} else {
Log.i("UN SUCCESSFUL", "onFailure: Failed to upload data to server");
handler.sendEmptyMessage(MSG_FAIL);
}
......
答案 2 :(得分：1)
您收到错误
java.lang.RuntimeException：无法在线程内创建处理程序 没有调用Looper.prepare（）
因为你是从工作线程调用的。您需要从主线程中调用Toast.makeText()（以及处理UI的大多数其他函数）。你可以使用一个处理程序，
@Override
public void onResponse(Call call, Response response) throws IOException {
if (response.isSuccessful()) {
Log.i("SUCCESSFUL", "onSuccess: data uploaded");
context.runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(context, "SUCCESSFUL", Toast.LENGTH_SHORT).show();
}
});
}
答案 3 :(得分：0)
试试这个
Toast.makeText(YourActivity.this, "Your Message", Toast.LENGTH_SHORT).show();
<强>活动
post(URL, jsonData, new Callback() {
@Override
public void onFailure(Call call, IOException e) {
Log.i("FAILED", "onFailure: Failed to upload data to server");
//here I want to show toast message
Toast.makeText(YourActivity.this, "Your Message", Toast.LENGTH_SHORT).show();
}
@Override
public void onResponse(Call call, Response response) throws IOException {
if (response.isSuccessful()) {
Log.i("SUCCESSFUL", "onSuccess: data uploaded");
//here I want to show toast message
Toast.makeText(YourActivity.this, "Your Message", Toast.LENGTH_SHORT).show();
} else {
Log.i("UN SUCCESSFUL", "onFailure: Failed to upload data to server");
//here I want to show toast message
Toast.makeText(YourActivity.this, "Your Message", Toast.LENGTH_SHORT).show();
}
}
});
<强>片段
post(URL, jsonData, new Callback() {
@Override
public void onFailure(Call call, IOException e) {
Log.i("FAILED", "onFailure: Failed to upload data to server");
//here I want to show toast message
Toast.makeText(getActivity(), "Your Message", Toast.LENGTH_SHORT).show();
}
@Override
public void onResponse(Call call, Response response) throws IOException {
if (response.isSuccessful()) {
Log.i("SUCCESSFUL", "onSuccess: data uploaded");
//here I want to show toast message
Toast.makeText(getActivity(), "Your Message", Toast.LENGTH_SHORT).show();
} else {
Log.i("UN SUCCESSFUL", "onFailure: Failed to upload data to server");
//here I want to show toast message
Toast.makeText(getActivity(), "Your Message", Toast.LENGTH_SHORT).show();
}
}
});
修改
Handler handler = new Handler();
handler.runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(mContext, "Your Message", Toast.LENGTH_SHORT).show();
}
});
答案 4 :(得分：0)
试试这个
TaskActivity.this.runOnUiThread(new Runnable() {
@Override
void run() {
Toast msg = Toast.makeText(TaskActivity.this,
"message", Toast.LENGTH_LONG);
msg.show();
});
答案 5 :(得分：0)
只需在调用此方法时发送活动的上下文：
void methodName(Context c){
post(URL, jsonData, new Callback() {
@Override
public void onFailure(Call call, IOException e) {
Log.i("FAILED", "onFailure: Failed to upload data to server");
//here I want to show toast message
}
@Override
public void onResponse(Call call, Response response) throws IOException {
if (response.isSuccessful()) {
Log.i("SUCCESSFUL", "onSuccess: data uploaded");
Toast.makeText(c,"message",Toast.LENGTH_SHORT).show();
//here I want to show toast message
} else {
Log.i("UN SUCCESSFUL", "onFailure: Failed to upload data to server");
//here I want to show toast message
}
}
});
}