读取 PNG 签名失败: 文件不以 PNG 签名开始

I'm not sure if it's a valid solution, but deleting only the file mentioned in the error message helped. While deleting the folder, containing it didn't.

Steps

1. In build.gradle

aaptOptions {
cruncherEnabled = false
}

2. Delete content inside C:\Users\.gradle\caches (or ~/.gradle/caches for Mac and Linux)
3. Restart Android Studio

Creating the .apk of an application all the resources are analyzed, if some resource has an incorrect format or is corrup you will get the message:

.png failed to read PNG signature: file does not start with PNG signature

Be sure to have the correct resources, you can check it by opening your file.

You might have used a JPEG file or some other image file format.

Use PNG images to solve the error.

Drawable directory can only have png type of images.

It's likely a JPG renamed to a PNG file, not an actual PNG file
The problem could be because of the wrong extension of images.

In my case, the file was a JPEG image but it was saved as PNG not converted to. In this situation change extension to the real one and convert to PNG then retry.

For instance, you have ic_logo.png but it's actually a JPG image.
You should rename it back to ic_logo.jpg and use something like Photoshop to convert the image to PNG format.

This is a result of wrong file type indeed and can be fixed by saving the files in correct format.

I ran into this issue with PhoneGap Build and wanted to leave my 2 cents for any other PhoneGap / Cordova user who might also run into this.

My problem was that I upgraded my old PhoneGap 6.x to 8.0 and it seems behaviour of the default splash has changed. It used to require jpg as a default splash, but on 8.0 it results in this error on production builds.

This worked before:

<splash src="www/splash.jpg" />

Now you have 2 options. Replace the default splash with png like this:

<splash src="www/res/screen/android/screen-xhdpi-portrait.png" />

Other option is to remove default splash entirely.

For a quick fix ,Make shrinkResources to false instead of true in app.gradle Hope this will help. if Not then also add this aaptOptions { cruncherEnabled = false }

i have same error for slow i do some step:

1. open abc_btn_switch_to_on_mtrl_00001.9.png (Image)file in paint
2. now select png and save as and re-save in drawable and overweight in with old images and its work

If you don't have any transparent pixels, then renaming the file to .jpg worked for me.

android {
buildTypes {
release {
crunchPngs false // or true
}
}
}














buildTypes {
debug {
signingConfig signingConfigs.debug
}
release {
crunchPngs false // or true


lintOptions {
checkReleaseBuilds false
abortOnError false
}
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}

This occurs due to the incorrect extension given to the image. For example, the image is jpg and the extension given is png.

Solutions:

1. Add { cruncherEnabled = false } in build.gradle
2. Convert the image into png rather than just changing the extension.

I've had the same issue. To solve it just restart your Android Studio and build the gradle file again.

I had the same issue, solved by converting the images to webP from Android studio right-click on the image -> tap on Convert to WebP

the conversion will handle file formating and also reduce the size of the PNG

If you are using an online platform to generate App Icon(launcher_icon), then use PNG Format or First convert JPEG to PNG and then used APP ICON GENERATOR

In my case also there was a jpg file instead of png, so I changed my extension and solve my problem.

You can add code in node_modules/react-native/react.gradle. After doFirst

doLast {
def moveFunc = { resSuffix ->
File originalDir = file("$buildDir/generated/res/react/release/${resSuffix}");
if (originalDir.exists()) {
File destDir = file("$buildDir/../src/main/res/${resSuffix}");
ant.move(file: originalDir, tofile: destDir);
}
}
moveFunc.curry("drawable-ldpi").call()
moveFunc.curry("drawable-mdpi").call()
moveFunc.curry("drawable-hdpi").call()
moveFunc.curry("drawable-xhdpi").call()
moveFunc.curry("drawable-xxhdpi").call()
moveFunc.curry("drawable-xxxhdpi").call()
moveFunc.curry("raw").call()
}

check it if it not fix issue after remove drawable folder github enter link description here

I was able to fix it permanently.

I created a new blank expo project, then I added a new app icon (correct png format), then I ejected from expo.

I then copied the mipmap-* folders from the blank project to my real project. It all worked perfectly.

You can open the images with windows win10 'Paint', then you can save as .png and overrite it, It will solve the problem

Failed to read PNG signature - Just put 1 line in your build.gradle

 buildTypes {
release {
minifyEnabled true
shrinkResources true
crunchPngs false  // Paste this line
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}

Open [Root_project]/app/build.gradle and add following lines.

release {
...


crunchPngs false // or true


lintOptions {
checkReleaseBuilds false
abortOnError false
}


...
}

if you are facing this issue in Flutter while buildings apk then add crunchPngs false

android {
buildTypes {
release {
...
crunchPngs false
}
}

into android/app/build.gradle

I was getting the same error when signing APK.

This solution fixed the problem:

build.gradle(:app):

...
aaptOptions {
cruncherEnabled = false
}
...

You can check for more: https://developer.android.com/studio/build/optimize-your-build