[英]How can I set the Textview on the basis of a condition?
我想根據特定條件設置TextView的文本。 我正在從Firebase中獲取一個值,並將其存儲在名為pestBinaryValue的變量中。 獲取的值是1或0。基於此值,我想更改TextView的文本。 有人可以幫我解決這個問題嗎...
這是JAVA代碼
package com.example.android.greenharvest;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
public class PestDetails extends AppCompatActivity {
TextView pestUpdate;
DatabaseReference firebase;
public String pestBinaryValue;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_pest_details);
pestUpdate = findViewById(R.id.textViewPest);
FirebaseUser user= FirebaseAuth.getInstance().getCurrentUser();
String userid=user.getUid();
firebase = FirebaseDatabase.getInstance().getReference("/0/users").child(userid);
firebase.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
pestBinaryValue = dataSnapshot.child("pest").getValue().toString();
Toast.makeText(PestDetails.this,pestBinaryValue,Toast.LENGTH_LONG).show();
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
if(pestBinaryValue=="1"){
pestUpdate.setText("Pest Has Been Detected!");
}
if(pestBinaryValue=="0"){
pestUpdate.setText("No Pests!");
}
}
}
這是XML代碼:
<?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"
android:id="@+id/pest_details">
<include
android:id="@+id/include"
layout="@layout/toolbar_layout" />
<TextView
android:id="@+id/profile_heading"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
android:text="@string/pest_details"
android:textAlignment="center"
android:textColor="@color/colorHomescreen"
android:textSize="30dp"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.487"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.12" />
<ImageView
android:id="@+id/imageView3"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="@+id/include"
app:layout_constraintVertical_bias="0.26"
app:srcCompat="@drawable/baseline_bug_report_black_18dp" />
<TextView
android:id="@+id/textViewPest"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
android:text="Pest is present!"
android:textColor="#000"
android:textSize="26dp"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="@+id/include" />
</android.support.constraint.ConstraintLayout>
pestBinaryValue=="1"
這是不正確的語法。
pestBinaryValue.equals("1") //is proper.
pestBinaryValue == 1 //this is for an int value.
如果存儲在數據庫表中的值已經是Boolean類型,則還可以更改以下幾行:
>public String pestBinaryValue;
>pestBinaryValue = dataSnapshot.child("pest").getValue().toString();
>if(pestBinaryValue=="1"){
pestUpdate.setText("Pest Has Been Detected!");
}
if(pestBinaryValue=="0"){
pestUpdate.setText("No Pests!");
}
對此:
>public Boolean pestBinaryValue;
>pestBinaryValue = dataSnapshot.child("pest").getValue();
>if(pestBinaryValue)
pestUpdate.setText("Pest Has Been Detected!");
else
pestUpdate.setText("No Pests!");
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