问题:
将id为“ readOut”的textView设置为wifi信号强度的值测试
码:
class wifi {
int signalStrength = 0;
int loopToggle = 0;
Context context = MainActivity.this;
@RequiresApi(api = Build.VERSION_CODES.ICE_CREAM_SANDWICH)
public void loop() throws InterruptedException {
while (loopToggle == 0) {
WifiManager signalStrength = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
String wifiInfo = WifiManager.EXTRA_WIFI_INFO;
TextView textView = (TextView) textView.findViewById(readOut);
Thread.sleep(1000);
}
}
}
布局文件:
<?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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.wifilocator.MainActivity">
<TextView
android:id="@+id/readOut"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="filler"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
感谢您的任何帮助,您可以提供!
最佳答案
如果您使用xml属性R.id.readOut
引用View
,则必须编写android:id="@+id/readOut"
所以整行应该是
TextView textView = (TextView) textView.findViewById(R.id.readOut);
R代表R类,该类将生成以包含您在应用程序中所需的各种资源。