Android App crashes only with release APK

Question

I have a curious issue. I built an app that works fine in debug mode (direkt debugging to my phone and with debug APK installed on my phone) but the app crashes at one point if I use the release build APK. I found the point where the app crashes with release APK, but I don't know why and what I can do:

protected final String TABLE = "done";
protected final String COL_ID = "_id";
protected final String COL_TASK = "taskid";
protected final String COL_DATE = "donedate";

protected String getLastDoneDate(String id) {
    String date = "";

    String filter = COL_TASK + " LIKE ?";
    String[] filterArgs = new String[] {id};
    String sortOrder = COL_DATE + " DESC";
    String[] columns = new String[] {COL_DATE};
    Cursor c = MyTime.db.query(TABLE, columns, filter, filterArgs, null, null, sortOrder, "1");
    if (c.moveToFirst()) {
        date = c.getString(c.getColumnIndex(COL_DATE));
    }
    c.close();

    return date;
}

If I remove the line Cursor c = ... (and all according to c) it works.

Database looks like that:

CREATE TABLE IF NOT EXISTS done (
                _id INTEGER PRIMARY KEY autoincrement,
                taskid INTEGER,
                donedate TEXT DEFAULT '');

Gradle Snippet:

buildTypes {
    release {
        shrinkResources false
        minifyEnabled true
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
    debug {
        shrinkResources false
        minifyEnabled true
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}

I can not debug to find the problem because the crash does'nt happen while debugging.

Can somebody help me to solve this issue?

Answer 1

I added debuggable = true to my gradle file and found the reason of my problem.

buildTypes {
release {
    shrinkResources false
    debuggable true
    minifyEnabled true
    proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
debug {
    shrinkResources false
    minifyEnabled true
    proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}

Table "done" was not created because I tried to put two table create statements into a single db.execSQL()

Answer 2

Except for the SQLite, you can check proguard-rules.pro file, it maybe makes release.apk crash. if you want to lean more, click https://developer.android.com/studio/build/shrink-code.html