I have created a simple counter application for Android. I have just started using support libraries and just to test it out, I wanted to show a snackbar which says Hello . Here is my code in the MainActivity.java file :
package com.mapsup.counter;
import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import com.google.android.material.snackbar.Snackbar;
public class MainActivity extends Activity {
long count=0;
TextView tv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_layout);
SharedPreferences sp=getApplicationContext().getSharedPreferences("preferences",Context.MODE_PRIVATE);
count=sp.getLong("count",0);
tv=findViewById(R.id.counter);
tv.setText(String.valueOf(count));
//Create and display a snackbar
Snackbar snackbar = Snackbar.make(tv,"Hello",Snackbar.LENGTH_LONG);
snackbar.show();
}
public void increase(View view) {
++count;
tv.setText(String.valueOf(count));
}
public void decrease(View view) {
if(count>0) {
--count;
tv.setText(String.valueOf(count));
}
}
public void reset(View view) {
count=0;
tv.setText("0");
}
@Override
public void onStop() {
super.onStop();
Context ctx=getApplicationContext();
SharedPreferences sp=ctx.getSharedPreferences("preferences",Context.MODE_PRIVATE);
SharedPreferences.Editor editor=sp.edit();
editor.putLong("count",count);
editor.apply();
}
}
Here is the layout main_layout.xml file :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#0031A0"
android:orientation="vertical"
android:padding="20dp"
android:id="@+id/root">
<TextView
android:id="@+id/counter"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginBottom="20dp"
android:layout_weight="1"
android:background="#B2FFFFFF"
android:gravity="center"
android:textSize="36sp" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="increase"
android:text="@string/add"
android:textSize="30sp" />
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="decrease"
android:text="@string/subt"
android:textSize="30sp" />
</LinearLayout>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="reset"
android:text="@string/reset"
android:textAllCaps="false"
android:textSize="30sp" />
</LinearLayout>
When I am running the app, the app crashes. The logcat shows this as the error message :
2020-02-03 00:20:10.015 12849-12849/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.mapsup.counter, PID: 12849
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mapsup.counter/com.mapsup.counter.MainActivity}: android.view.InflateException: Binary XML file line #26: Binary XML file line #26: Error inflating class <unknown>
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2724)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2789)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1527)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:203)
at android.app.ActivityThread.main(ActivityThread.java:6251)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
Caused by: android.view.InflateException: Binary XML file line #26: Binary XML file line #26: Error inflating class <unknown>
Caused by: android.view.InflateException: Binary XML file line #26: Error inflating class <unknown>
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Constructor.newInstance0(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:430)
at android.view.LayoutInflater.createView(LayoutInflater.java:645)
at com.android.internal.policy.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:58)
at android.view.LayoutInflater.onCreateView(LayoutInflater.java:717)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:785)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:858)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:821)
at android.view.LayoutInflater.inflate(LayoutInflater.java:518)
at android.view.LayoutInflater.inflate(LayoutInflater.java:426)
at com.google.android.material.snackbar.Snackbar.make(Snackbar.java:164)
at com.mapsup.counter.MainActivity.onCreate(MainActivity.java:23)
at android.app.Activity.performCreate(Activity.java:6712)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2677)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2789)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1527)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:203)
at android.app.ActivityThread.main(ActivityThread.java:6251)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
Caused by: java.lang.UnsupportedOperationException: Failed to resolve attribute at index 6: TypedValue{t=0x2/d=0x101009b a=1}
at android.content.res.TypedArray.getColorStateList(TypedArray.java:531)
at android.widget.TextView.<init>(TextView.java:805)
at android.widget.TextView.<init>(TextView.java:727)
at android.widget.TextView.<init>(TextView.java:723)
at java.lang.reflect.Constructor.newInstance0(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:430)
at android.view.LayoutInflater.createView(LayoutInflater.java:645)
at com.android.internal.policy.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:58)
at android.view.LayoutInflater.onCreateView(LayoutInflater.java:717)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:785)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:858)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:821)
at android.view.LayoutInflater.inflate(LayoutInflater.java:518)
at android.view.LayoutInflater.inflate(LayoutInflater.java:426)
at com.google.android.material.snackbar.Snackbar.make(Snackbar.java:164)
at com.mapsup.counter.MainActivity.onCreate(MainActivity.java:23)
at android.app.Activity.performCreate(Activity.java:6712)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2677)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2789)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1527)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:203)
at android.app.ActivityThread.main(ActivityThread.java:6251)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
The app runs all fine if I remove the snackbar code. According to my thinking, creating a snackbar is the same as creating a toast, we just need to replace Toast
with Snackbar
. Is this correct?
What is my mistake and how to properly use a snackbar?
Please replace tv to rootLayout in Snackbar.make(llRootLayout,"Hello",Snackbar.LENGTH_LONG); as below.
public class MainActivity extends Activity {
long count=0;
TextView tv;|
LinearLayout llRootLayout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_layout);
SharedPreferences sp=getApplicationContext().getSharedPreferences("preferences",Context.MODE_PRIVATE);
count=sp.getLong("count",0);
tv=findViewById(R.id.counter);
llRootLayout=findViewById(R.id.root);
tv.setText(String.valueOf(count));
//Create and display a snackbar
Snackbar snackbar=Snackbar.make(llRootLayout,"Hello",Snackbar.LENGTH_LONG);
snackbar.show();
}
public void increase(View view) {
++count;
tv.setText(String.valueOf(count));
}
public void decrease(View view) {
if(count>0) {
--count;
tv.setText(String.valueOf(count));
}
}
public void reset(View view) {
count=0;
tv.setText("0");
}
@Override
public void onStop() {
super.onStop();
Context ctx=getApplicationContext();
SharedPreferences sp=ctx.getSharedPreferences("preferences",Context.MODE_PRIVATE);
SharedPreferences.Editor editor=sp.edit();
editor.putLong("count",count);
editor.apply();
}
}
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