ive been trying to acomplish swipe down to refresh,what i wanna do is when i swipe down i want it to refresh the value in testviewsw1,but how ever whenever i try to do it, it doesnt even have the swipe thing. but have no idea why its just not working at all, ive already found some help from another website, but still got this error keep on showing up, really need help, its about my graduation project.please help me guys, really appreciate all helps form everyone.
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:background="@drawable/background"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.widget.SwipeRefreshLayout
android:id="@+id/swiperefresh"
android:layout_width="393dp"
android:layout_height="570dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.421"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.595" />
<ScrollView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="212dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.196"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="1.0"
tools:ignore="MissingConstraints">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:ignore="MissingPrefix,ScrollViewSize">
<TextView
android:id="@+id/testviewSw1"
android:layout_width="128dp"
android:layout_height="38dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:text="燈泡1值"
android:textSize="24sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.358"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.577"
tools:ignore="HardcodedText,SpUsage" />
</RelativeLayout>
</ScrollView>
<Button
android:id="@+id/area_set"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="52dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="60dp"
android:text="Button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.951"
tools:ignore="HardcodedText,RtlCompat" />
<ImageButton
android:id="@+id/listenbutton2"
android:layout_width="82dp"
android:layout_height="60dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="4dp"
android:background="@drawable/micro"
android:cropToPadding="false"
android:onClick="listenButtonOnClick"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.835"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.842"
tools:ignore="ContentDescription,OnClick" />
<TextView
android:id="@+id/resultTextView"
android:layout_width="337dp"
android:layout_height="187dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="88dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toTopOf="@+id/listenbutton"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.508"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.17"
tools:ignore="UnknownIdInLayout" />
<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="36dp"
android:layout_marginStart="68dp"
android:layout_marginTop="8dp"
android:text="區域設置"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintVertical_bias="0.03"
tools:ignore="HardcodedText,RtlCompat,UnknownId" />
<TextView
android:id="@+id/textView5"
android:layout_width="68dp"
android:layout_height="18dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="36dp"
android:text="語音控制"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.732"
app:layout_constraintStart_toEndOf="@+id/textView4"
app:layout_constraintVertical_bias="0.0"
tools:ignore="HardcodedText,UnknownId,UnknownIdInLayout" />
<TextView
android:id="@+id/textView6"
android:layout_width="379dp"
android:layout_height="44dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:background="#59fffac0"
android:text="首頁"
android:textAlignment="center"
android:textSize="30sp"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.454"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0"
tools:ignore="HardcodedText" />
<Switch
android:id="@+id/switch1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:switchMinWidth="56dp"
android:text="Switch1:"
android:textOff="OFF"
android:textOn="ON"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.817"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.582"
tools:ignore="HardcodedText,RtlHardcoded" />
</android.support.constraint.ConstraintLayout>
----------
----------
private String led;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.home_main);
// 下拉更新↓
final SwipeRefreshLayout swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swiperefresh);
final TextView textView = (TextView) findViewById(R.id.testviewSw1);
mySwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener()
{
@Override
public void onRefresh() {
swipeRefreshLayout.setRefreshing(true);
(new Handler()).postDelayed(new Runnable() {
@Override
public void run() {
swipeRefreshLayout.setRefreshing(false);
JsonObject obj = new JsonObject();
ObjectMapper mapper = new ObjectMapper();
below is my logcat
12-11 13:03:42.320 5420-5420/com.example.aaa.text E/InputEventReceiver: Exception dispatching input event. 12-11 13:03:42.320 5420-5420/com.example.aaa.text E/MessageQueue-JNI: Exception in MessageQueue callback: handleReceiveCallback 12-11 13:03:42.320 5420-5420/com.example.aaa.text E/MessageQueue-JNI: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.view.View.canScrollVertically(int)' on a null object reference at android.support.v4.widget.SwipeRefreshLayout.canChildScrollUp(SwipeRefreshLayout.java:678) at android.support.v4.widget.SwipeRefreshLayout.onInterceptTouchEvent(SwipeRefreshLayout.java:701) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2108) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2197) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2197) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2197) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2197) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2197) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2197) at com.android.internal.policy.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2403) at com.android.internal.policy.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1737) at android.app.Activity.dispatchTouchEvent(Activity.java:2765) at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:69) at com.android.internal.policy.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2364) at android.view.View.dispatchPointerEvent(View.java:9514) at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4230) at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4096) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3695) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3661) at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3787) at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3669) at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3844) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3695) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3661) at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3669) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642) at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:5922) at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:5896) at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:5857) at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:6025) at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185) at android.os.MessageQueue.nativePollOnce(Native Method) at android.os.MessageQueue.next(MessageQueue.java:323) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5417) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 12-11 13:03:42.320 5420-5420/com.example.aaa.text D/AndroidRuntime: Shutting down VM 12-11 13:03:42.321 5420-5420/com.example.aaa.text E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.aaa.text, PID: 5420 java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.view.View.canScrollVertically(int)' on a null object reference at android.support.v4.widget.SwipeRefreshLayout.canChildScrollUp(SwipeRefreshLayout.java:678) at android.support.v4.widget.SwipeRefreshLayout.onInterceptTouchEvent(SwipeRefreshLayout.java:701) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2108) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2197) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2197) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2197) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2197) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2197) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2553) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2197) at com.android.internal.policy.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2403) at com.android.internal.policy.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1737) at android.app.Activity.dispatchTouchEvent(Activity.java:2765) at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:69) at com.android.internal.policy.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2364) at android.view.View.dispatchPointerEvent(View.java:9514) at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4230) at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4096) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3695) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3661) at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3787) at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3669) at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3844) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3695) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3661) at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3669) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642) at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:5922) at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:5896) at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:5857) at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:6025) at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185) at android.os.MessageQueue.nativePollOnce(Native Method) at android.os.MessageQueue.next(MessageQueue.java:323) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5417) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
and below is my solutaion
final SwipeRefreshLayout swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swiperefresh); //抓 燈泡1值得layout final TextView textView = (TextView) findViewById(R.id.testviewSw1);
swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener()
{
@Override
public void onRefresh() {
swipeRefreshLayout.setRefreshing(true);
ObjectMapper mapper = new ObjectMapper();
JsonNode actualObj = null;
try {
actualObj = mapper.readTree(led);
} catch (IOException e) {
e.printStackTrace();
}
JsonNode ledObj = actualObj.get("led");
int xx = ledObj.get("led17").asInt();
System.out.println("led:" + ledObj.get("led17"));
if (xx == 1 ){
tx1.setText("燈泡1:開");
}
else if (xx == 0) {
tx1.setText("燈泡1:關");
}
}
});
